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Section1

“How To”

In this section, I discuss key questions important in taking a der-matologic history and their implications, as well as specific der-matologic lesions and what they tell us. Furthermore, I introducevarious tests important in veterinary dermatology, give theirindications, explain necessary techniques in detail, and discussthe interpretation of the results.

Dermatologic HistoryClinical signs for various skin diseases are very similar and theetiology of a patient’s problem may not be apparent based solelyon the findings of a clinical examination. A thorough historywill typically provide clues in regard to the cause of the skin dis-order and allow the veterinarian to prioritize time-consumingand frequently costly laboratory tests needed to confirm the diag-nosis. I prefer my clients to fill out a questionnaire in the waitingroom which we then review together during the consultation.This decreases the time needed to extract a good history fromthe owner, helps ensure a complete history independent of stresslevels and time constraints, and allows the client to think abouther or his pet’s skin problem for a little while without unneces-sarily delaying the appointment schedule. A sample of a derma-tology questionnaire is enclosed in the Appendix. It is importantto phrase questions appropriately, because many owners leave outpertinent facts either because they are not aware of their rele-vance or because they think these facts may not be well receivedby the veterinarian. Sometimes, it is necessary to ask the samequestion several times in different ways to obtain meaningfulanswers. I cannot overemphasize the importance of taking a goodand efficient dermatologic history, which requires tremendousknowledge, experience, practice, and effective communicationskills. To teach this is beyond the scope of this book. However, Ido discuss some crucial questions and their implications in moredetail.

Question: What is the breed of the patient?

Relevance✓ Some breeds are predisposed to certain skin diseases and it

may be worthwhile to keep a list of such breed predispositionsin easy reach.

✓ A list of reported breed predisposition is given in the Appendix. But beware, breed predispositions may vary withgeographic location!

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Question: How old was the patient when clinical signs were first recognized?

Relevance✓ Very young animals (puppies and kittens) are more commonly

presented with congenital and hereditary defects, ectopara-sites such as Sarcoptes scabiei, Otodectes cynotis, or Demodex canis, infections with bacteria (impetigo) or fungi (dermatophytosis) or, in dogs, canine juvenile sterile granulo-matous dermatitis and lymphadenitis.

✓ Young adult dogs are more commonly affected by demodico-sis, atopic dermatitis, and flea-bite hypersensitivity, as well as idiopathic seborrhea and follicular dysplasia.

✓ In middle age, hormonal diseases become a significant consid-eration, although allergies still occur in a significant number of animals, particularly in cats.

✓ Neoplastic diseases are more commonly seen in older animals.

Question: How long has the disease been present and how did it progress?

Relevance ✓ Acute onset of severe pruritus is frequently associated with

scabies. Food adverse reaction may also have an explosive onset.

✓ If pruritus was the first initial sign and lesions occurred later, then atopy or food-adverse reaction are most likely. Pruritus with lesions that occur at approximately the same time may be due to a wide variety of causes.

✓ Chronic nonlesional pruritus is typically due to atopic der-matitis or food adverse reaction, possibly complicated by sec-ondary infections. Scabies incognito may also cause nonles-ional pruritus.

✓ If cutaneous signs have been present for years without the development of concurrent systemic signs, endocrine disor-ders are unlikely.

✓ Nonpruritic alopecia for years without systemic signs points towards alopecia and follicular dysplasias or hereditary alopecia.

✓ The presence of chronic wounds alone or associated with draining tracts necessitates the search for an infectious organism.

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Diagnostic procedures: Scabies treatment trial, skin scrapingselimination diet, cytology, bacterial culture, fungal culture, biopsy.

Question: Where on the body did the problem start?

Relevance Tables 1-1 and 1-2 outline typically affected sites ofcertain diseases.

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Question: Is the animal itchy?

Relevance✓ Pruritus is sometimes difficult to identify. Owners often do not

consider licking, rubbing, or biting as clinical signs indicative of pruritus (we all have heard the story of the dog who is con-stantly licking its feet because "it is a very clean dog …"). Several

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Table 1-1Location of Lesions and/or Pruritus of

Various Canine Skin Diseases

LOCATION OF LESIONS COMMON UNDERLYING DISEASESAND/OR PRURITUS

Otitis externa

Pinnae

Tail base

Head/face

Paws

Claws

Atopy, food adverse reaction, parasites, polyps.Secondary infections are common and can also occur with primary endocrine disease!

Atopy, food adverse reaction, scabies, vasculitis, pemphigus foliaceus

Demodicosis, atopy, food adverse reaction, dermatophytosis, insect allergies, scabies, dis-coid lupus erythematosus, pemphigus foliaceus

Bacterial or fungal infection, trauma, immune-mediated skin diseases.

Flea-bite hypersensitivity

Table 1-2Location of Lesions or Pruritus of

Various Feline Skin DiseasesLOCATION OF LESIONS COMMON UNDERLYING DISEASESAND/OR PRURITUS

Otitis externa

Pinnae

Tail base

Head/face

Paws

Claws

Atopy, food adverse reaction, parasites, polyps.Secondary infections common!

Notoedres cati, vasculitis, pemphigus foliaceus

Atopy, food adverse reaction, dermatophytosis,insect allergies, feline scabies, pemphigus foliaceus

Atopy, food adverse reaction, pemphigus foliaceus, trauma, plasmacytic pododermatitis

Bacterial infection, trauma, immune-mediated skin diseases

Flea-bite hypersensitivity

Demodicosis, atopy, food adverse reaction,Malassezia dermatitis, pemphigus foliaceus,metabolic epidermal necrosis.

routine questions may be needed to identify pruritus in some patients: Are they licking or chewing their paws? Are they rubbing their faces? Do they scoot on their rear ends? Are they scratching their armpits?

✓ The presence of pruritus with skin lesions does not help muchin discovering the etiology of the pruritus, given that many skin diseases cause pruritus. However, pruritus without lesionstypically means either atopic dermatitis or food adverse reac-tion (possibly with secondary infections) or in rare instances scabies incognito.

✓ The perceived severity of pruritus may vary with the owner. Some owners deny the presence of pruritus despite the patient's frantic scratching in the consultation room. Others insist on severe pruritus in a patient with no evidence of self-trauma on clinical examination. Good communication skills and judgement are essential to form a realistic opinion for evaluation. If the pet's scratching wakes the owner up at night, the pruritus is severe irrespective of the presence of lesions.

✓ If itch preceeds the occurrence of lesions, atopic dermatitis, food adverse reaction, and scabies incognito must again be considered.

Diagnostic procedures: Trichogram in alopecic patients thatare reportedly nonpruritic.

Question: Is the disease seasonal?

Relevance ✓ Insect bite hypersensitivities (caused most commonly by fleas, but

mosquitoes or other insects can also be involved) frequently cause disease that worsens in summer. Whether clinical signs are absent or milder in the colder season depends on specific environmental conditions.

✓ Atopic dermatitis may also be seasonal in certain climates. In many temperate climates it may occur more noticeably in spring and summer if caused by tree and grass pollens or worsens in sum-mer and autumn because of weed pollens. Warmer climates such as those found in tropical or subtropical regions usually have an extended pollen season. Hypersensitivities to house dust mites are often nonseasonal, but may be seasonally worse in winter in some areas and patients.

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✓ Seasonal noninflammatory alopecia and hyperpigmentation may be due to cyclic follicular dysplasia.

Diagnostic procedures: Insect bite trial, intradermal skin test-ing, serum testing for allergen-specific IgE, biopsy, keeping theanimal inside to evaluate for mosquito-bite hypersensitivity.

Question: Are there other clinical signs such as sneezing, coughing, or diarrhea?

Relevance ✓ Sneezing, coughing, wheezing, and conjunctivitis may be seen

concurrently with atopic dermatitis and caused by airborne allergies.

✓ Diarrhea may be associated with food adverse reaction.

✓ Polydipsia and polyuria are common with iatrogenic and idio-pathic hyperadrenocorticism.

✓ Systemic mycoses frequently present with concurrent anore-xia, lethargy, and with gastrointestinal or respiratory symp-toms.

Diagnostic procedures: Cytology of nasal exudate or conjunctiva,elimination diet, urine cortisol/creatinine ratio, low dose dexametha-sone suppression test, and adrenocorticotropic hormone (ACTH)-stimulation test.

Question: What is fed to the animal? Was a special diet used in the past? What was it and how long was it fed exclusively?

Relevance ✓ Knowing the diet will allow the clinician to determine possi-

ble nutritional deficiencies.

✓ It will also help in formulating an elimination diet if indicated (p. 46).

✓ If a diet was fed in the past and it was not a true elimination diet (was not fed exclusively or not fed for an appropriate length of time) it may need to be repeated.

� Contrary to the common belief, food adverse reactions typicallydo not occur immediately after a change in feeding habits. Most animals with food adverse reactions have been consuming the offending diet for years before showing clinical signs.

� Remember to ask about treats and supplements, which are often forgotten, when food is discussed with the client.

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Question: Are there other animals in the household? Do they show cutaneous symptoms?

Relevance ✓ If other animals in the household are similarly affected, conta-

gious disease such as dermatophytosis or scabies is more likely.

� Other animals may serve as a reservoir for ectoparasites without showing clinical signs.

Diagnostic procedures: If indicated, insect control trial, fungalcultures, or scabies treatment trials should include all animals inthe household to identify and/or treat possible carrier animals toallow successful long-term remission for the patient.

Question: Does any person in the household have skin disease?

Relevance✓ Two zoonoses of major concern in veterinary dermatology are

scabies and dermatophytosis (ringworm). However, even if owners are not affected, these diseases cannot be ruled out.

✓ Canine scabies affecting humans occurs as an itchy papular rash in contact areas, such as arms and legs, starting days to weeks after onset of pruritus in the pet.

✓ Dermatophytosis is often characterized by scaling and ery-thema and may not be particularly pruritic, but occasionally can present as severely inflammatory and pruritic skin disease.Dermatophytosis may sometimes be misdiagnosed as eczema in humans.

✓ Sporotrichosis and other mycoses have zoonotic potential andmay occasionally cause disease in humans.

✓ Don’t forget that the skin disease of the owner may also be completely unrelated to the animal’s skin disease.

Diagnostic procedures: Wood’s light, skin scrapings, fungal cul-ture, scabies trial treatment. In severe forms of suspected der-matophytosis, a biopsy and special fungal stains may prove usefulfor obtaining a quick diagnosis.

Question: Was the disease treated before? If so, which drugs were used and how successful was treatment?

Relevance Response to previous therapy can be of tremendoushelp in establishing or ruling out underlying causes for the skindisease.

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✓ Initial response to recent glucocorticoid administration may not be helpful because many skin diseases improve for a shortperiod with this symptomatic, nonspecific treatment.

✓ Repeated response to low-dose glucocorticoid therapy sug-gests hypersensitivities (possibly complicated by Malasseziadermatitis caused by Malassezia pachydermatis).

✓ Repeated response to antibiotics and glucocorticoids in combination is of little help.

✓ Repeated partial or total response to antibiotics indicates a pyoderma usually secondary to either atopic dermatitis, food adverse reaction, hormonal disease, or another less common disorder that is suppressing the skin's immune system. In addition to antibacterial treatment, the underlying problem needs to be identified and treated to prevent recurrences.

� Ask specifically how much the pet improved while receiving medication because many owners tend to judge a treatment asnot helpful if it did not cure the disease.

Question: What is currently used to control fleas?

Relevance ✓ Flea-bite hypersensitivity is the most common hypersensi-

tivity and an extremely common skin disease in most small animal practices. If flea-bite hypersensitivity is suspected, a flea control trial should be commenced.

✓ Details of the flea control for all animals in the household areimportant because in a severely allergic animal, clinical signs can be caused by a very small number of flea bites. Inconsi-stent or ineffective flea control can be discovered only through detailed questioning.

� Many owners take questions about their flea control as an insult to their own cleanliness and hygiene. Good communica-tion skills are a great help. I own a flea-allergic dog and rou-tinely mention her as an example, which breaks the ice and increases the client’s willingness to listen and follow my instructions.

Question: When was the last medication given?

Relevance ✓ Recent administration of medication may affect the clinical

presentation.

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✓ It may also affect various indicated diagnostic tests that may need to be postponed.

✓ Long-term glucocorticoid therapy will affect the results of allergy tests – both intradermal skin testing and serum testing for allergen-specific IgE. It will also affect histopathologic findings and the results of many blood tests.

✓ Antihistamines and short-term systemic and topical glucocor-ticoids (i.e., < 4 weeks) may influence intradermal skin testing.

✓ Some antibiotics, such as trimethoprim-sulfonamide combina-tions, will affect blood concentrations of thyroxin. Others such as cephalosporins may affect the glucose readings of some urine test strips.

✓ Remember to ask specific questions regarding heartworm pre-vention, vitamin supplements, or deworming which are also forms of pharmacotherapy.

Question: Does the animal get better with a change of environment (a weekend away or a day at the in-laws for example)?

Relevance✓ The animal's improvement in another environment indicates

involvement of an environmental allergen (airborne or con-tact) or irritant.

✓ Lack of improvement does not rule out these allergies, in that airborne and contact allergens may be the same in different locations (house dust mites are found almost anywhere in the world).

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DermatologicExaminationA good dermatologic examination requires adequate lighting, asystematic and thorough approach, and should always include ageneral physical examination. Observation from a distance shouldbe followed by close inspection of skin and mucous membranes. Istart at the head, look at the lips, mouth, ears, run my handsthrough the coat of the trunk, lift up the tail to inspect the peri-anal area, and then examine the legs and feet with pads and claws.Next, the patient is rolled on his back – reluctant small pets aremade to sit up in the lap of the owner; with larger dogs the frontpaws are lifted up for a short moment, which gives me the oppor-tunity to examine the animal's ventral aspects from the axillae tothe groin.

General ObservationLocalized or Generalized Problem

✓ Localized problems may be due to infectious organisms that gainedentry at a certain site and spread only locally such as atypicalmycobacterial or fungal infections.

✓ Neoplastic disease is commonly localized, at least initially.

✓ Generalized disorders are more commonly due to hypersensitivitiesor systemic conditions such as endocrine disorders and immune-medi-ated or metabolic skin diseases.

Symmetry

✓ Bilaterally symmetric lesions are typically caused by internaldisease such as hypothyroidism, hyperadrenocorticism, or pemphi-gus foliaceus. Allergies may also present with bilaterally symmetricsymptoms.

✓ Asymmetric lesions more commonly have external causes such asectoparasites (e.g., demodicosis) or fungi (e.g., dermatophytosis).

Haircoat Quality, Color, and Shine

✓ Is the haircoat dull or shiny? A dull haircoat may be due to meta-bolic or hormonal diseases, nutritional deficiencies, or chronic skindisease.

✓ Are there color abnormalities or changes and if so, did they occur

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before or concurrent with the onset of skin disease or as a conse-quence of the disease. Hair color changes may be associated withhormonal disease or follicular dysplasia.

✓ Changes in the hair quality (either to a coarse coat or to afine puppy coat) may again point to hormonal disease or follicu-lar dysplasia. Close inspection of the skin and mucous membranes follows thegeneral observation. Pay special attention to any individuallesions. Primary lesions are initial eruptions that are causeddirectly by the underlying disease process. Secondary lesionsevolve from primary lesions or are caused by the patient (self-trauma) or environment (medications). It is important that theclinician be able both to differentiate between primary and sec-ondary lesions and to understand the underlying pathomech-anism because this helps in the formulation of a relevant list ofdifferential diagnoses. I next discuss the individual lesions andtheir implications and give the most common differential diag-noses for each lesion.

Primary LesionsMacule

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Figure 1-1AMacule

Definition: A focal, circumscribed,nonpalpable change in color <1 cm(when it is larger, it is termed apatch). Pathogenesis: Pigmentationchange due to decreased or increasedmelanin production, erythema due toinflammation or local hemorrhagecaused by trauma or vasculitis.

Figure 1-1BMacule

Differential diagnoses-depigmenta-tion: Vitiligo, discoid lupus erythemato-sus, uveodermatologic syndrome, mucocu-taneous pyoderma. Differential diagnoses-hyperpigmen-tation: Lentigo, hormonal diseases orpost-inflammatory with a multitude ofpossible underlying causes lentigo.Differential diagnosis-erythema:Inflammation due to a variety of underly-ing diseases or hemorrhage due to vascu-lopathies or coagulopathies.

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Papule

Pustule

Figure 1-2APapule

Definition: A solid elevation of up to1 cm in diameter. Larger lesions arecalled plaques. Pathogenesis: Influx ofinflammatory cells into the dermis,focal epidermal hyperplasia, earlyneoplastic lesions.

Figure 1-2BPapule

Differential diagnoses: Bacterialfolliculitis, demodicosis, fungal folli-culitis, flea-bite and mosquito-bitehypersensitivity, scabies, contact aller-gy, autoimmune skin disease, drugeruption.

Figure 1-3APustule

Definition: A small circumscribedarea within the epidermis filled withpus. Pathogenesis: Most pustules arefilled with neutrophils, but eosino-philic pustules may also be seen.Aspiration cytology and biopsy areindicated. (Courtesy of Dr. ThierryOlivry.)

Figure 1-3BPustule

Differential diagnoses- neutrophils: Bacterial infection, fun-gal infection, autoimmune skin disease.Differential diagnoses-eosinophils:Insect or contact hypersensitivity, para-sites, immune-mediated skin disease

Vesicle

Figure 1-4AVesicle

Definition: A small circumscribedarea within or below the epidermisfilled with clear fluid. Larger vesiclesare called bullae. Vesicles are veryfragile and thus transient.Pathogenesis: Spongiosis and extra-cellular fluid collection due to inflam-mation and loss of cohesion.(Courtesy of Dr. Thierry Olivry)

Figure 1-4BVesicle

Differential diagnoses: Immune-mediated and congenital skin diseases, viral diseases, or irritant dermatitis.

Wheal

Figure 1-5AWheal

Definition: A sharply circumscribed,raised, edematous lesion that appearsand disappears within minutes tohours. Pathogenesis: Subcutaneousedema.

Figure 1-5BWheal

Differential diagnoses: Urticaria,insect bites, other hypersensitivities,drug eruption.

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Nodule

Figure 1-6ANodule

Definition: A circumscribed, solidelevation more than 1 cm in diame-ter that extends into deeper layers ofthe skin. Pathogenesis: Massive infil-tration of inflammatory or neoplasticcells into the dermis and subcutis ordeposition of fibrin and crystallinematerial.

Figure 1-6BNodule

Differential diagnoses: Sterile gran-ulomatous diseases, bacterial or fungalinfections, neoplastic diseases, calci-nosis cutis

Tumor

Figure 1-7ATumor

Definition: A large mass involvingskin or subcutaneous tissue.Pathogenesis: Massive influx ofinflammatory or neoplastic cells.

Figure 1-7BTumor

Differential diagnoses: Sterile gran-ulomatous diseases, bacterial or fungalinfections, neoplastic diseases.

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AlopeciaFigure 1-8Alopecia

Definition: Partial to complete loss of hair.Pathogenesis: Self-trauma, damage to the hairor hair follicle due to dysplasia, inflammationand/or infection, lack of hair regrowth oftendue to hormonal disease.

Differential diagnoses: Primary lesion infollicular dysplasias, endocrine disorders, telo-gen effluvium, anagen defluxion. Secondarylesion in pruritic skin diseases, bacterial orfungal folliculitis, demodicosis.

Scale

Figure 1-9AScale

Definition: An accumulation of loosefragments of the horny layer of theskin. Pathogenesis: Increased produc-tion of keratinocytes (often associat-ed with abnormalities of the kera-tinization process) or increased reten-tion of corneocytes.

Figure 1-9BScale

Differential diagnoses: Primarylesion in follicular dysplasias, idiopathicseborrheas and ichthyosis. Secondarylesion in diseases associated with chronicskin inflammation.

Primary or Secondary Lesions

Crust

Figure 1-10ACrust

Definition: Adherence of dried exudate, serum, pus, blood, scales, or medications to the skin surface.

Figure 1-10BCrust

Differential diagnoses: Primarylesion in idiopathic seborrhea, zinc-responsive dermatitis, metabolic epi-dermal necrosis. Secondary lesion in avariety of skin diseases.

Follicular Castcular cast

Figure 1-11AFollicular cast

Definition: An accumulation of ker-atin and follicular material to the hairshaft.

Figure 1-11BFollicular cast

Differential diagnoses: Primarylesion in vitamin A-responsive der-matosis, idiopathic seborrhea, andsebaceous adenitis. Secondary lesionin dermatophytosis and demodicosis.

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Pigmentary Abnormalities

Figure 1-12AHyperpigmentation

Definition: Increased epidermaland/or dermal melanin. Pathogenesis:Increased production, size, or mela-nization of melanosomes or increasednumber of melanosomes due to avariety of intrinsic or extrinsic fac-tors. Most common cause: Chronicinflammation

Figure 1-12BHyperpigmentation

Differential diagnoses: Primarylesion in endocrine dermatoses, sec-ondary postinflammatory change dueto a variety of skin diseases.

Comedo

Figure 1-13AComedones

Definition: A dilated hair folliclefilled with corneocytes and sebaceousmaterial. Pathogenesis: Primary kera-tinization defects or hyperkeratosisdue to hormonal abnormalities orinflammation.

Figure 1-13BComedones

Differential diagnoses: Primarylesion in feline acne, some idiopathicseborrheas, Schnauzer comedo syn-drome, endocrine diseases. Secondarylesion in demodicosis, and less com-monly dermatophytosis.

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Hyperpigmentation

Secondary Lesions

Figure 1-14AEpidermal collarette

Definition: Scale of loose keratinflakes or "peeling" keratin arranged ina circle. Pathogenesis: Remnant of apustule or vesicle after the top part(the "roof") has been lost, or causedby a point source of inflammation,such as a papule.

Figure 1-14BEpidermal collarette

Differential diagnoses: Most likelybacterial infection, less commonly fun-gal infection, immune-mediated skindisease, insect-bite reaction, or contacthypersensitivity.

Erosion

Figure 1-15AErosion

Definition: A shallow epidermal defectthat does not penetrate the basal mem-brane. Pathogenesis: Trauma or inflam-mation leads to rapid death and/or lossof keratinocytes

Figure 1-15BErosion

Differential diagnoses: Variousskin diseases associated with self trau-ma such as infections or allergies.

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Epidermal Collarette

Ulcer

Figure 1-16AUlcer

Definition: Focal loss of epidermiswith exposure of underlying dermisPathogenesis: Severe trauma and/ordeep and severe inflammation

Figure 1-16BUlcer

Differential diagnoses: Various skindiseases associated with trauma such asinfections and allergies, also immune-mediated diseases.

Lichenification

Figure 1-17ALichenification

Definition: Thickening and harden-ing of skin characterized by exagger-ated superficial skin markings.Pathogenesis: Chronic trauma such asfriction or rubbing.

Figure 1-17BLichenification

Differential diagnoses: All chronicand pruritic skin diseases.

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Specific Tests in SmallAnimal Dermatology

CytologyIndications Any pruritic, scaly, odoriferous, or alopecic animal should beevaluated for evidence of bacterial or fungal infection. Thus,cytology is indicated for almost all patients presented with skindisease. Skin scrapings, aspirations, impressions, ear swabs andtape preparations are different techniques to obtain cytologicsamples.

✓ A superficial skin scraping is used in areas such as the inter-digital skin where impression smears may be difficult to obtain.It is also used when the skin is normal, slightly moist, or greasy.

✓ An aspirated sample is useful in the evaluation of pustulecontent and intracutaneous or subcutaneous nodules.

✓ An impression smear is used when moist or oily skin with oozing or discharging lesions is evaluated.

✓ Ear swabs are used to evaluate ear canals.

✓ Dry scaly skin maybe evaluated by tape preparations. Thistechnique is also frequently used in the interdigital area whereimpression smears may be difficult to obtain.

Technique 1. Skin scraping for cytology

✓ Affected skin is exposed and the surface of the skin scrapedvery gently and superficially with a scalpel blade in the directionof hair growth.

✓ The debris collected on the blade is applied to a slide and spreadwith the blade in a “buttering the bread” motion (Figure 1-18).

2. Aspiration of nodules

✓ Aspiration from nodules or abscesses is undertaken with a 12-ml syringe and a 22-ga needle. THE SKIN SHOULD BE DISINFECTED

BEFORE SAMPLING.

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✓ The nodule is firmly grasped and the needle is then inserted(Figure 1-19), aspirated several times (up to the 10-ml mark ifpossible), the pressure released, and the syringe with needle stillattached is withdrawn.

✓ It is important to release the pressure before withdrawal of theneedle or else the aspirate can be sucked back into the barrel ofthe syringe – from which it may not be retrieved.

✓ The needle is detached, the plunger pulled back, and the needle reattached.

✓ Cells are then blown onto a slide. The smear is air dried.

3. Impression Smears

✓ Cotton swabs are used to obtain samples from ear canals byinserting them into the canal, rotating, and withdrawing them.They are then rolled gently onto a slide. I hold ear slides uni-formly on the left side with my left hand, the cotton swab fromthe left ear is rolled onto the mid-section of the slide and the cot-ton swab from the right ear onto the right third of the same slide.

✓ In patients with dry skin, a cotton swap may be moistenedwith saline solution and rubbed on the surface of affected skinbefore it is rolled onto a slide.

✓ In patients with moist or greasy skin, the slide can be rubbedor impressed directly onto affected skin (Figure 1-20).

4. Tape Preparation

✓ A direct impression technique uses clear sticky tape to collectdebris from the surface of the skin. Although quick, this methoddoes take practice to establish what is "normal."

✓ The tape is pressed sticky side down onto the skin (Figure 1-21).

✓ Next, it is pressed (also sticky side down) onto a drop of meth-ylene blue or the blue stain of DiffQuick on a slide (Figure 1-22).

✓ The tape serves as a cover slip: the sample can be evaluatedeven under oil immersion (with a small droplet of oil placeddirectly on top of the tape).

✓ This technique is especially useful for Malassezia evaluation.Other items of interest that can be identified include inflamma-tory cells such as neutrophils (which may have passed throughthe epidermis in response to a superficial infection), nucleatedepithelial cells (which are not normal and reflect a keratinizationabnormality), cocci, rods, macrophages, short-bodied demodexmites, Cheyletiella, and occasionally Sarcoptes mites.

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Figure 1-18Debris collected with a superficial skinscraping is spread onto a slide with a"butter the bread" motion.

Figure 1-19Aspiration of a small nodule.

Figure 1-20Impression smears are obtained by gentlypressing a slide onto affected skin.

Figure 1-21The tape is pressed sticky-side down ontoaffected skin.

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Stain✓ A modified Wright's stain (e.g., DiffQuick) can be used to stainthe air-dried slides. It is much faster and easier than Gram's stainand sufficient to evaluate nearly all skin cytology samples. ButGram's stain is also suitable.

Interpretation✓ Yeast organisms are most often M. pachydermatis (Figure 1-23),although Candida spp. may occasionally be involved.

✓ Cocci are most often Staphylococcus intermedius (Figure 1-24). S. aureus or Streptococci may be found in some patients.

✓ Rod-shaped organisms are found mostly in the ear canal and aremost often Pseudomonas aeruginosa or Proteus mirabilis (Figure 1-25).

� The number of organisms is important. Occasional cocci oryeast are probably not relevant. On the skin, I consider one ormore yeast organisms per high-power field (HPF) relevant; coccishould be seen in high numbers. In the infected ear, yeast andcocci typically occur in high numbers; any rods present areabnormal. Don't mistake exogenous bacterial contaminants forinfection.

✓ Inflammatory cells with intracellular organisms are pathogno-monic for a clinically relevant infection (Figure 1-26).

✓ Eosinophils typically indicate allergic or parasitic skin disease.

� Neoplastic cells may be difficult to recognize so that the helpof a clinical pathologist is typically needed. Even with high skilllevels, neoplastic skin disease should not be diagnosed exclusivelyby cytology (with the exception of mast cell tumors); a biopsyshould always confirm any suspicions raised clinically and cyto-logically.

✓ If mast cells are found cytologically (Figure 1-27), the diagnosisof mast cell tumor is confirmed, but complete surgical excisionshould still be confirmed by histopathology. In some patients withmast cell tumors, mast cell granules do not stain with routineDiffQuick and thus a negative cytologic result can not rule out mas-tocytosis.

✓ Acantholytic cells are keratinocytes that have lost their intercellu-lar connections (desmosomes) and present as round cells with a pur-ple cytoplasm and a central dark purple nucleus (Figure 1-28). Thesecells suggest pemphigus foliaceus or erythematosus but can also beseen on cytologic samples of severe pyodermas. A biopsy is indicatedto confirm the diagnosis.

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Figure 1-22Tape is then pressed sticky-side downonto a drop of methylene blue on a slide.

Figure 1-23Malassezia pachydermatis on a tapepreparation stained with blue stain ofDiffQuick (original magnification x400).

Figure 1-24Cocci on an impression smear stainedwith DiffQuick (original magnificationx1000).

Figure 1-25Rods on an impression smear obtainedfrom otitis externa and stained withDiffQuick (original magnificationx1000).

� Remember, that bacterial and yeast infections are usuallysecondary to other diseases, which need to be identified andtreated to prevent recurrence of the infection.

� Cytologic re-evaluation at the end of antimicrobial therapyis crucial because organisms may change during treatment. Forinstance, a dog initially presented with bacterial infection maydevelop a yeast infection during successful antibacterial treat-ment, preventing clinical improvement and vice versa.

Treatment of bacterial infections and antifungal therapy are discussed in Section 3.

Superficial Skin ScrapingsIndicationsAny pruritic or scaly dog and cat may be infested withCheyletiella spp., Otodectes cynotis, Scabies scabiei, or Notoedres-cati and should be scraped.

Technique✓ If scabies is suspected, preferred areas for scrapings are theelbows, hocks, and ventrum. Ear margins should be scraped thoroughly if any pruritus or scaling is observed in this area.Sometimes scaling is subtle and only becomes evident on closeexamination.

✓ Sites are gently clipped with #40 clipper blades. Mites may bedifficult to find (especially canine scabies mites), so that the big-ger the surface area scraped, the greater will be the chance of apositive skin scraping.

� Several drops of mineral oil are applied directly to theclipped skin and distributed evenly in the area.

✓ The oil is scraped off with a #11 scalpel blade (Figure 1-29)and transferred to one or more glass slide(s). Scrape 10 to 15times especially when canine scabies is suspected.

✓ A cover slip is used to allow rapid yet thorough evaluation ofcollected debris (Figure 1-30) and the slide(s) is (are) evaluatedunder low power (x40 or x100) systematically from the left uppercorner to the right lower corner.

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Figure 1-26Neutrophils with intracellular cocci(arrow) pathognomonic for bacterialinfection stained with DiffQuick (origi-nal magnification x1000).

Figure 1-27Mast cells on an aspirate from a felinemast cell tumor stained withDiffQuick (original magnificationx1000).

Figure 1-28Acantholytic cells on an aspirate of anintact pustule from a dog with pemphigusfoliaceus stained with DiffQuick (originalmagnification x1000).

Figure 1-29A scalpel blade is used to scrape appliedoil off the affected and clipped skin.

InterpretationA finding of one mite or egg of Sarcoptes spp., Notoedres cati,Cheyletiella spp. or Otodectes cynotis (Figures 1-31, 1-32, and 1-33) is diagnostic for the cause of the skin disease. Negative scrap-ings do not rule out the presence of mites and clinical disease par-ticularly in canine scabies. Cheyletiella spp. and Otodectes cynotis mayalso be missed by superficial skin scrapings. The next step would bea therapeutic trial (p. 49), possibly in conjunction with other diag-nostic tests such as an elimination diet (p. 46) to evaluate othercauses of pruritus.

Deep Skin ScrapingsIndicationAny dog or cat with possible demodicosis must be scraped. Thus,every alopecic patient and every patient with papules, pustules,crusting, and particularly interdigital pododermatitis must bescraped for the presence of demodicosis. Effective deep skin scrap-ings of paws may require sedation or general anesthesia.

Technique� Because Demodex canis and felis mites live deep in the hair folli-cle, it is useful to squeeze the skin as hard as the patient can toleratebefore scraping in an attempt to push mites out from the depths ofthe follicles.

� A blade covered with mineral oil should be used in the direc-tion of hair growth until capillary bleeding is observed (Figure 1-34).

� Feet and faces are hard to scrape, so that it may be worthwhile toscrape erythematous areas adjacent to papules and crusts interdigital-ly to maximize the yield and to minimize bleeding associated withscraping. Hair plucks may be useful for those areas, the plucked hairis placed in a drop of mineral oil on a slide, with a cover slip andevaluated microscopically for the presence of mites (p. 38).

✓ Negative scrapings or hair plucks of interdigital areas do not ruleout pododemodicosis; a biopsy may be needed to confirm or rule outthe diagnosis.

✓ Old English Sheepdogs, Scottish Terriers and especially Shar-peismay produce negative results on scrapings and may have to be biop-sied for diagnosis. Although not documented, it is thought thatthese breeds have more tortuous and deeper hair follicles.

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Figure 1-30…and the oil and gathered debris aretransferred to a slide.

Figure 1-31Sarcoptes scabiei mites and eggsobtained with a superficial skin scrap-ing from a dog with scabies (originalmagnification x40).

Figure 1-32Cheyletiella parasitivorax (original magnification x40).

Figure 1-33Otodectes cynotis mites and eggs (original magnification x40). (Courtesy of Dr.Peter Ihrke.)

✓ The finding of more than one mite should be considered diagnostic.

Interpretation✓ It is important to assess the relative numbers of adults (bothlive and dead), larvae/nymphs and eggs (Figure 1-35) per lowpower field (LPF) and to record the site of scraping. During sub-sequent visits, assessment of response to therapy relies on thecomparison of such numbers, so we routinely repeat scrapes atthe same sites monthly when monitoring cases with demodicosis.

Treatment for demodicosis is outlined in Section 3.

Wood’s Lamp ExaminationIndicationAny dog or cat with possible Microsporum canis infection shouldbe examined with a Wood’s lamp. Any patient with alopecia,papules, pustules, and/or crusts may benefit from the procedure.

Technique✓ The Wood’s lamp should be warmed up for 5 minutes before usebecause the stability of the light’s wavelength and intensitydepends on temperature.

✓ The animal is examined under the lamp in a dark room.

� Hairs invaded by M. canis may show a yellow-green fluores-cence. This fluorescence runs along the hair shafts (Figure 1-36)rather than fluorescing on discrete, individual, occasional scales, asmay be seen in normal animals and humans.

✓ Some drugs, soaps, and bacteria such as Pseudomonas aeruginosamay also cause fluorescence but are usually not associated with hairshafts.

Interpretation✓ In approximately 50% of all infections with M. canis, greenishfluorescence of tryptophan metabolites is seen under ultravioletlight at 253.7 nm.

✓ Positive fluorescence is diagnostic for dermatophytosis and byfar the most common fluorescing dermatophyte in veterinary medi-cine is M. canis. Some other dermatophytes may show fluorescence,but these are not relevant in veterinary dermatology.

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Figure 1-34To evaluate a patient for demodicosis,scrapings must be deep, until capillarybleeding is observed. The skin should besqueezed to maximize the yield.

Figure 1-35Demodex canis (A) mite and (B) egg(original magnification x100).

Figure 1-36Green fluorescent hair shafts underWood’s lamp examination in a cat infected with M. canis.

�A lack of fluorescence does not rule out dermatophytosis. Fungalculture and/or biopsy are the next steps.

Treatment of dermatophytosis is outlined in Section 3.

Fungal CultureIndication A fungal culture may be indicated in any dog or cat with possible fun-gal infection and thus in any patient with alopecia, papules, pustules,and/or crusts.

Technique✓ Hairs and scale from the edge of a lesion (preferably the ones fluor-escing under the Wood's lamp) should be taken (Figure 1-37).

✓ If lesions are not well circumscribed or if asymptomatic carriers aresuspected, I recommend the McKenzie tooth brush method. In thistechnique, the hair is brushed with a sterile toothbrush (any newtooth brush in a sealed package is sufficiently sterile mycologically).Scales and loose hairs caught in the tooth brush are gently imprintedonto the agar (Figure 1-38).

✓ Sabouraud's agar is the most common medium for fungal cultures.In practice dermatophyte test medium (DTM) is frequently used.DTM is essentially a Sabouraud agar with a color indicator and addedingredients to inhibit overgrowth with saprophytes and bacteria.

�After being innoculated, the culture jars should be incubated atbetween 25º and 30º C at 30% humidity, or in a warm dark cornerwith the lids not screwed down tightly.

✓ Cultures should be incubated for 2 to 3 weeks and must be evaluat-ed daily.

Interpretation�A pH change (and subsequent color change) that occurs as thecolony grows indicates dermatophytes (Figure 1-39). These fungi useprotein and produce alkaline metabolites which cause the pH andcolor change. It is imperative that the color change is observed coinci-dentally with the development of the colony. Color changes also occurin association with mature (i.e., large) saprophyte colonies. Saprophytesinitially utilize carbohydrates. Once all carbohydrates have been usedand the colony is already grown (Figure 1-40), they turn to the proteinsand rapidly change the color and pH with the subsequent

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Figure 1-37Hairs and scales from the edge of skinlesions are chosen for fungal culture.

Figure 1-38Contents of a tooth brush are transferredto a fungal culture medium after usingthe McKenzie toothbrush technique.

Figure 1-39A dermatophyte culture changes thecolor of the dermatophyte test mediumin early stages of growth.

Figure 1-40A large saprophyte colony prior to colorchange.

alkaline metabolites (Figure 1-41). It may be impossible to distinguishon gross appearance whether a mature colony with significant red pig-mentation to the underlying and surrounding agar is a pathogenic orsaprophytic fungus.

✓ Always check the colony microscopically for characteristic macro-conidia. Clear sticky tape is impressed gently onto the culture (stickyside down), then laid onto a drop of methylene blue or the blue stainof DiffQuick (also sticky side down) on a microscope slide and evalu-ated under the microscope. The surface of the sticky tape acts as itsown cover slip. If required, microscope oil can be placed directly ontothe surface of the tape.

✓ Microsporum canis grows in a white, wooly colony with a yellowishreverse pigment (which maybe difficult to assess if grown on DTM).Abundant spindle-shaped macroconidia with knobs at the terminalends and typically more than six internal compartments are seenmicroscopically (Figure 1-42).

� M. canis is a zoophilic fungus and patients typically wereinfected by another animal or human. Humans and other ani-mals in contact with the patient are at risk to develop the infec-tion or may be asymptomatic carriers and need to be carefullyevaluated and possibly treated as well.

✓ M. gypseum grows in a granular beige culture with yellowishreverse pigment and has thin-walled echinulate macroconidia withfewer than six internal compartments (Figure 1-43). M. gypseum isa geophilic fungus that is acquired by exposure to contaminatedsoil and thus has a limited zoonotic potential.

✓ Trichophyton mentagrophytes grow in colonies of variabletexture and color that characteristically have a few cigar-shapedmacroconidia and globous microconidia (Figure 1-44). Typicalhosts for T. mentagrophytes are rodents and humans; infectionsare usually associated with exposure to these hosts or theirimmediate environment.

See Section 3 for treatment of dermatophytosis

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Figure 1-41Saprophyte colony of Figure 1-4024 hours later.

Figure 1-42Hyphae and macroconidia ofMicrosporum canis.

Figure 1-43Hyphae and macroconidia ofMicrosporum gypseum.

Figure 1-44Hyphae and microconidia of Trichophytonmentagrophytes.

TrichogramIndicationTrichograms may be useful in any alopecic animal as well as inanimals with suspected dermatophytosis and associated papules,pustules, or crusting.

Technique✓ A forceps is used to forcefully pluck hairs from affected skin(Figure 1-45).

✓ The hairs are then placed onto a slide and evaluated underlow power. I generally use mineral oil and a cover slip to preventthe hair sample from blowing all over the table rather thanremaining under the microscope (Figure 1-46).

InterpretationA trichogram is taken for several reasons:

✓ To determine how many hairs are in telogen (or resting) versusanagen (or growing) phase (in shedding or suspected endocrineproblems). This requires practice! Anagen-phase bulbs are rounded,smooth, shiny, glistening and soft so the root may bend (Figure 1-47).Telogen bulbs are club- or spear-shaped with a rough surface(Figure 1-48). A sample with exclusively or mostly telogen hairspoints to an endocrine disorder or follicular arrest.

✓ To determine if a cat or dog creates hair loss by licking or rub-bing, or if the hair falls out for another reason. If the animal is pru-ritic and licks the hair off, the tips of the hairs are broken off(Figure 1-49). Any trauma to the hair shaft, such as occurs in der-matophytosis or anagen defluxion, may also cause hair with brokenends. If the hair falls out for other reasons, the tips are tapered(Figure 1-50).

✓ Trichograms are used routinely in human dermatology to evalu-ate alopecias, but their usefulness in veterinary dermatology hasnot been explored in any great detail and is hampered by themarked variations in breed characteristics.

�A trichogram is most useful to determine if bald cats thatpresent with a history of "nonpruritic" alopecia are really so-called"closet lickers" or "hidden groomers" (in which case the hair-shaftends will be fractured) or if the hair falls out due to telogen effluvi-um or, very rarely, for hormonal reasons.

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Figure 1-45A forceps is used to pull hairs from affected skin for a trichogram.

Figure 1-46The hairs are placed in oil onto a slideunder a cover slip.

Figure 1-47Anagen bulbs in a trichogram of a normal dog (original magnificationx100).

Figure 1-48Telogen bulb in a trichogram of a dogwith hyperadrenocorticism (original magnification x100).

� Trichograms may also be used to diagnose canine demodicosis.If mites are found microscopically, the diagnosis is confirmed.However, if no mites are present, demodicosis cannot be ruled out!

� Trichograms can also help to diagnose color-diluent alopecia.In this disease the melanin in the hair shaft is present in bigclumps rather than finely dispersed as in normal pigmented hair.

BiopsyIndication✓ Any skin that appears unusual to the clinician should be biopsied.

✓ A biopsy should also be considered if lesions fail to respond toappropriate empiric therapy.

✓ Nodules are possibly neoplastic and should be biopsied.

✓ The presence of any suspected disease for which treatment isexpensive and/or life-threatening should be confirmed histopatho-logically.

✓ One of the major reasons to perform a skin biopsy is to rule outother diagnoses (“I think this is an allergy but... ”). In such a situa-tion, the biopsy report of “chronic hyperplastic dermatitis withmononuclear perivascular infiltrate” has at least ruled out commoninfectious agents and unusual dermatoses. A supportive pathologicdiagnosis interpreted in conjunction with the clinical impressionsmay be just as useful as a confirmatory diagnosis.

TechniqueSelection of the Site✓ Selection of the site requires careful examination of the entire ani-mal for the most representative samples, identification of the primaryand secondary lesions present, and the formation of a list of differen-tial diagnoses before biopsy.

�With the exception of a solitary nodule, we recommend takingmultiple tissue samples. These should include primary lesions if pres-ent, contain a representative range of lesions, and above all, shouldbe taken and handled carefully. A normal sample of haired skinshould also be included.

✓ Depigmenting lesions should be biopsied in an area of activedepigmentation (gray color) rather than the final stage (white or pink color).

✓ Alopecia should be biopsied in the center of the worst area as wellas in junctional and normal areas.

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✓ Ulcers and erosions should not be biopsied. Do not expect apathologist to be able to describe more specifically than “an ulcer” if an ulcer is biopsied or “a crusted erosion” if an excoriated area is selected.

Preparation of the Site✓ With the exception of excision biopsies of nodules, no surgicalpreparation of the site should be employed. Even topical applicationof alcohol and air drying may alter the epidermis.

� If crusts are present, these should be left on the skin. If theyare accidentally dislodged they should still be placed in the for-malin and a note “please cut in crusts” should be added to therequest form. Crusts may contain microorganisms or acantholyticcells that will help to obtain a diagnosis. Infection as a result oflack of surgical preparation does not seem to be a problem.

Wedge versus Punch Biopsy✓ There are two commonly employed biopsy techniques in veter-inary medicine–the punch biopsy and the wedge biopsy. The lat-ter is commonly employed as an excisional technique whenremoving solitary nodules. It is also indicated with vesicles(which are typically too fragile to survive a punch biopsy with-

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Figure 1-49Hair tips are broken off in an alopeciccat with atopic dermatitis (original magnification x100).

Figure 1-50Tapered hair tips from an alopecic areaof a dog with hyperadrenocorticism(original magnification x100).

out rupturing), suspected cases of panniculitis (in which suffi-cient depth of biopsy may not be achieved with a punch) andwhen biopsying the edge of a lesion in a spindle shape (whichallows correct orientation of the lesion in the laboratory wherespindle-shaped lesions are always cut in longitudinally).

✓ The punch biopsy is quick, relatively atraumatic, and usuallyemployed with suspected infectious, inflammatory, and endocrine der-matoses. Disposable biopsy punches are readily available in varioussizes. They can be cold-sterilized and reused.

�With the exception of face and foot biopsies, 8 mm punchesshould be used! Smaller punches with a diameter of 4 or 6 mm areemployed to biopsy face and feet. Very small punches (i.e., 2 to 3 mm)are not useful in small animal practice with the exception of eyelidbiopsies.

✓ The overlying hair is clipped and gently removed and the biopsysite is marked with a water-proof marker pen (Figure 1-51). If crustsare present, using scissors may be less traumatic.

�General anesthesia is indicated for nasal or footpad biopsies. I use a combination of ketamine at 5 mg/kg bodyweight and diazepamat 0.25 mg/kg body weight given intravenously in one syringe. No fur-ther preparation is necessary. If the biopsy is to be performed undermanual restraint or with sedation (I use xylazine at 0.4 mg/kg ormedetomidine at 10 mcg/kg intravenously), then a subcutaneousinjection of 1ml xylocaine (or the less stinging prilocaine) withoutadrenaline will usually provide adequate local anesthesia (Figure 1-52).If the agent is administered subcutaneously with the needle entrypoint outside the proposed biopsy area, there should be no disruptionto the biopsy.

�Don't overdose small animals with lignocaine (> 1ml / 5 kg), sincethis can cause cardiac arrhythmias.

�Allow 3 to 5 minutes for the local anesthetic to have effect.

✓ If a punch is used, it is held at right angles to the surface of the skinand gently placed over the selected lesion (Figure 1-53). Firm continu-ous pressure is applied and the punch is rotated in one direction (notecarefully!) until a sufficient depth has been reached to free the dermisfrom its underlying attachment. The punch is removed and any bloodshould be carefully blotted.

✓ The section of tissue is grasped at the base–which should be thepanniculus–and subcutaneous attachments severed (Figure 1-54).Under no circumstances should the dermis or epidermis be graspedwith forceps because this leads to a “crush artifact.” Crushed tissuemay be misinterpreted as scarring at best, and at worst renders thesample worthless. The tissue is rolled on gauze to gently blot the blood

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Figure 1-51The biopsy site is gently clipped andmarked with a water-proof marker pen.

Figure 1-52Local anaesthetic is injected subcuta-neously.

Figure 1-53The punch is placed vertically onto the surface androtated in only one direction.

Figure 1-54The sample is removed by grasping itsbase with a forceps and cutting it.

from its surface. A thin sample should then be placed with the pan-niculus face down–onto a rigid piece of cardboard or broken tonguedepressor (Figure 1-55). This prevents the tissue from curling whenplaced in the formalin optimizing the interpretation by the patholo-gist. Thick samples may be placed in formalin without such support.

✓ The unit of tissue and cardboard is placed in 10% formalin(tissue side down) and allowed to fix for several hours before sec-tioning. The volume of formalin required is at least 10 times thevolume of the sample. Nodules should be sectioned into 1 cmthick pieces to allow adequate penetration of the formalin intothe center of the lesion.

Submission of Biopsy Samples

� Careful completion of the appropriate skin biopsy requestform, including history and physical examination, will greatlyimprove the chances of a diagnostic report.

�A list of differential diagnoses is important with any clinicalcase but is essential with dermatologic patients. Seborrhea ordraining tracts can be the result of a wide range of diseaseprocesses. This list is important for the clinician to ensure thathe or she has considered all options and obtained as much infor-mation as possible from both pet and owner as necessary beforetaking the biopsy. It is also important for the pathologist andmay aid in choosing special stains to rule out or confirm unusualdiseases.

Serum Testing for Allergen-specific IgEIndication Useful if the owner of an atopic dog or cat diagnosed by history,clinical examination, and ruling out of differential diagnoses, iseither curious about what causes the problem or is interested inallergen-specific immunotherapy.

Interpretation✓ Different serum tests are available. Laboratory techniqueshave improved over the years and serum testing has become analternative to intradermal skin testing for many small animalpractitioners. However, tests vary in their sensitivity and speci-ficity so that careful selection of an appropriate test is important.

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✓ Testing for individual allergens rather than allergen groups isprudent to avoid immunotherapy with inappropriate allergens. Itis impossible to tell which of the allergens in a particular react-ing group are involved in the disease process.

✓ Results need to be interpreted in light of the clinical history of apatient. A dog with positive reactions to grass pollens only and a clin-ical history of nonseasonal pruritus for years in a temperate environ-ment such as in England or Canada will most likely not benefit fromallergen-specific immunotherapy.

✓ I still consider intradermal skin testing my first choice for theidentification of offending allergens in atopic dermatitis for severalreasons: 1) more individual allergens are used in skin testing than inserum testing; 2) the skin is the affected organ and thus it seemslogical to test the organ affected; and 3) the input of a veterinarydermatologist in regards to the interpretation of test results and man-agement of patients on allergen-specific immunotherapy is invalu-able for practitioners with limited experience in this particular field.

Bacterial CultureBacterial cultures are used infrequently in veterinary dermatology. Mostbacterial skin infections are caused by Staphylococcus intermedius. If cocciare identified on cytology, empiric antibiotic therapy is sufficient inalmost all patients.

Indication✓ Empiric therapy at appropriate doses for an appropriate time has failed to resolve the pyoderma (lesions are still present and cytology still reveals cocci).

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Figure 1-55If the biopsy specimen is thin, it is placedonto a cardboard or tongue depressorbefore placing it into formalin.

✓ Numerous rod-shaped bacteria are identified on cytology samplesfrom ear canals. These organisms may also rarely play a role in cuta-neous infections of patients clinically not responding to empiric therapy.

Procedure✓ Swabs are taken from ear canals as described for cytology samples.

✓ Aspirates from intact pustules are useful in patients withsuperficial pyoderma.

� Swabs from the skin surface to culture organisms frompatients with deep pyoderma are not suitable. Samples are takenin a similar manner to that used in biopsies under aseptic condi-tions (scrub the skin surface and use sterile instruments andgloves). The upper half of the tissue sample with the epidermisand hair is cut off and the lower half is submitted in a sterilecontainer placed on a sterile gauze pad soaked in a sterile salinesolution for maceration culture. This prevents overgrowth of theculture by surface bacteria not relevant to the deep infection.

� Each sample for culture and sensitivity should be accompa-nied by cytologic examination, and culture results must be inter-preted in relationship to cytologic findings.

Patch TestingThis is the test of choice to confirm contact allergy. In classic patchtesting, the test substance is applied onto intact skin (clipping is rec-ommended 24 hours earlier, to minimize any confusion due to clipperrash in a sensitive individual), covered with an impermeable sub-stance, and fixed. Human test kits are available (Figure 1-56).Alternatively, an area may be clipped and tape applied in a checker-board pattern to leave two, four, or six spaces of bare skin surroundedby areas covered by tape (Figure 1-57). Then individual antigens areplaced on to the bare patches and fixed with a tape. Fresh materialmay need to be cut up in small pieces and applied to the skin withthe help of an ophthalmic lubricant gel. On top of this taped area, awhole trunk bandage is applied (and fixed around the neck as well) toavoid movement of the bandage and the allergens (Figure 1-58).After 2 days, the patch is removed and reactions are observed. Afterremoving the bandage and allergens, the individual areas are markedwith a permanent marker pen (to make possible a second evaluation24 hours later). No reaction is graded as 0; erythema as 1+; erythemaand edema or induration as 2+; and erythema and vesiculation as 3+.

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Figure 1-56Human test kit on a dog. (Courtesy ofDr. Thierry Olivry.)

Figure 1-57Patch test using tape.

Figure 1-58Trunkal bandage covering the patch test site.

The latter two reactions are considered significant. The bandageshould then be reapplied (without taping and allergens) to avoid self-trauma and removed 24 hours later for a second evaluation. True con-tact allergy is characterized by a delayed-type reaction persisting orincreasing during these 24 hours without the allergen on the skin.

If neither erythema nor vesiculation is present, the reaction onthe previous day was probably caused by an irritant rather thanallergic dermatitis. Topical or systemic steroids must be with-drawn for 3 to 6 weeks before testing.

In open-patch testing, the allergen is rubbed into a marked testsite of normal skin and then examined daily over a 5-day period.The reactions similarly consist of mild erythema and edema. Thetechnique is suitable only for liquid or plant allergens (in whichcrushed leaves are used). An already sparsely haired clinicallyunaffected area, such as the medial thigh or the inner pinna, iscommonly used.

Diagnostic TrialsDiagnostic trials are well accepted tests in veterinary dermatology.They are performed when a certain problem is suspected and thetrial is either the only or the best way to diagnose the possibleunderlying disease. A response to the trial confirms the diagnosisin some instances (such as the scabies treatment trial), but inother instances a relapse after discontinuing the trial with subse-quent resolution on restarting the trial is diagnostic (such as inelimination diets). If there is no response to a well-conducteddiagnostic trial, the suspected disease is extremely unlikely(which helps veterinarian, owner, and patient, and needs to beemphasized to clients frustrated by the lack of response).

Elimination DietIndicationAn elimination diet is used to evaluate food adverse reactionwhich can occur with any food fed over a period of time. As ageneral rule food adverse reactions present infrequently. Any dogwith nonseasonal pruritus (particularly if the face, feet, or earsare affected) or recurrent pyoderma, or any cat with miliary der-matitis, noninflammatory alopecia, eosinophilic granuloma com-plex, or head and neck pruritus could possibly have an underly-ing food adverse reaction.

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Procedure� An elimination diet for dogs consists of one protein sourceand one carbohydrate source previously not fed! This meansthat the elimination diet for a particular patient is determinedby the diet fed so far to this animal. Cats are fed only one pro-tein without the carbohydrate source to enhance compliance.

✓ Possible options for proteins are chicken, turkey, duck, veni-son, mutton, beef, horse, buffalo, rabbit, hare, kangaroo, emu,various sorts of fish, among others. Carbohydrates may consist ofrice, potatoes, sweet potatoes, beans, or others.

✓ The diet chosen needs to be fed exclusively! Concurrentheart-worm prophylaxis or supplements must not contain foodflavor extracts.

✓ It may take 6 to 8 weeks before a response becomes evident.

� After initial improvement, a rechallenge with the normaldiet previously fed is essential because improvement may resultfrom other factors such as seasonal or environmental changes orconcurrent medication. If a relapse occurs within 2 weeks andclinical signs resolve again after reinstitution of the eliminationdiet, the diagnosis is confirmed.

Tips to increase compliance

✓ Warming the food may improve patient compliance.

✓ Spices such as garlic or salt (in small amounts) may also bebeneficial to improve palatibility.

� If the animal (and owner) is used to treats, the habit should becontinued in a modified fashion to prevent feeding of inappropri-ate proteins. Little pieces of the selected meat protein can be friedand kept in the fridge for use as treats. The selected meat can bedried (in the oven or microwave) and given as treats. If an animalis receiving potatoes in the diet, then fried pieces of potato may beused (so long as they are not fried in butter, but in a plant-derivedoil). If rice is chosen, rice cakes may be an additional option.

✓ If bones are part of the normal diet, bones of the meat selectedfor the elimination diet may be fed if available.

✓ Good client communication is essential. It must be made clearthat an occasional slip in feeding habits (as little as once or twiceweekly of a very small amount of a different protein) may destroyall the effort.

✓ It may be worthwhile to advise neighbors about the diet as well.

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✓ If a home-cooked diet is not an option, a commercial dietconsisting exclusively of a protein source and a carbohydratesource not previously fed may be considered. The same principlesapply to commercial as to home-cooked elimination diets.However, some animals with food adverse reactions may bemissed when using commercial diets.

After a diagnosis of food adverse reaction is confirmed, theclient has two options: 1. To continue a commercial eliminationdiet forever–the more convenient option; 2. A home-cookeddiet. It should be properly balanced (the help of a veterinarynutritionist may be indicated).

✓ Identifying of the offending allergen allows a more varied dietand is achieved through a sequential rechallenge with proteinsformerly fed. Beef, lamb, chicken, or cheese and milk productsare added to the elimination diet one at a time for 2 weeks each.If a relapse occurs within the first 2 weeks (many patients showsymptoms within the first 2 days), the protein is discontinueduntil the patient's condition settles. That particular protein isavoided in the future. After 2 weeks of a given protein withoutclinical symptoms, a reaction to this protein is ruled out and itmay be fed in the future. Some dogs will tolerate any home-cooked diet, but relapse on commercial diets may be caused by areaction to additives or preservatives.

Insect Control TrialIndicationAn insect control trial may be used in any patient with suspect-ed insect-bite hypersensitivities. Most animals with insect-bitehypersensitivities will be allergic to fleas. Clients generallyaccept these trials more readily when they are labeled “insectcontrol trials” because many do not believe fleas cause the prob-lem, whereas most will accept ants or mosquitoes as a possiblecause. Any dog with pruritus, alopecia, and/or a papular orcrusty rash in the tailbase or inguinal area, and any cat with mil-iary dermatitis, noninflammatory alopecia, or eosinophilic granu-loma complex may benefit from an insect control trial.Mosquito bite hypersensitivity in the cat is characterized bypapules and crusts on the nose, pinnae, and foot pads. A trialusing insect repellents may be beneficial to these animals.

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Procedure✓ The patient should be treated regularly with an insecticide. Ina diagnostic trial, I often increase the frequency of administrationabove the manufacturer’s recommendations. Fipronil spray, imida-cloprid, permethrin, and selamectin spot-ons are administeredevery 2 weeks. Pyrethroid sprays are administered daily dependingon the product. Nitenpyram tablets are given either daily or everyother day. Which products to use depends on the individual cir-cumstances. More details are provided on page 138.

✓ At the start of the trial, treat the animal’s environment withan insect-development inhibitor such as methoprene, fenoxycarb,or pyriproxifen. More details are provided on page 138.

✓ Contact animals (either living in the same household or thosethat visit on a regular basis) must be treated as well, althoughthe frequency between adulticide applications may be increasedto the manufacturers’ recommendations.

✓ At the start of the trial, I often prescribe 5 to 7 days of pred-nisolone at 1 mg/kg bodyweight daily to hasten clinical response.

If there is good response to the trial, insect-bite hypersensitivityis present and insect control may be tapered to the minimumrequired.

� Remember that the required minimum treatment typicallyvaries seasonally, as does the insect load.

Scabies Treatment TrialIndication Any pruritic dog or cat could possibly be infested with Sarcoptesscabiei or Notoedres cati, respectively, particularly if the prurituswas of sudden onset or if pinnae, ventrum, and elbows are pruri-tic. With spot-ons used for flea control, I have seen patients withpruritus and lesions limited to ventrum and lower legs. Negativesuperficial skin scrapings do not rule out scabies (p. 26) so trialtreatment is indicated in any patient with suspected scabies irre-spective of negative skin scraping results. In as much asCheyletiella spp. and Otodectes cynotis are sensitive to the sameantiparasitic agents, a scabies treatment trial will be useful forthese parasites as well.

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Procedure ✓ Several treatments for scabies are available but many of themare not labeled for this use.

✓ Topical treatments include ivermectin, lime sulfur dips, ami-traz, and other antiparasitic rinses. They are used weekly for 4weeks. More details are given on page 133.

✓ Systemic therapy may be undertaken with selamectin, iver-mectin or milbemycin. Treatment details are outlined on page 133.

✓ All animals in contact with the patient need to be treated as well!

✓ Initial deterioration during the first days of treatment mayoccur. Treat with glucocorticoids daily for 3 to 4 days at 1 mg/kgbody weight.

✓ Remission should be achieved within 4 weeks although somepatients may need extended treatment for up to 8 weeks.

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Section 2

The Approachto Common

DermatologicPresentations

In this section, I offer an approach to various common presenta-tions in veterinary dermatology. I begin each topic in this sec-tion with general comments followed by tables containing themost common differential diagnoses, their clinical features, diag-nostic procedures of choice, treatment, and prognosis. I haveattempted to list diseases in order of prevalence. Diseasesmarked with an (*) and a colored screen are potentially difficultto diagnose or their management often requires considerableexperience to achieve the best possible outcome. You may con-sider offering your client a referral to a veterinary dermatologistif you do not feel comfortable diagnosing or treating this disease.

This is not a textbook of veterinary dermatology so these tablesdo not contain all possible details but rather a concise overviewconcentrating on the most important features. Similarly, theflow charts at the end of each topic are concise and simplified tomaximize the benefit for the busy small animal practitioner.They will be useful in most instances, but remember that some ofyour clients may not have read the textbooks. Even though thisinformation is aimed at helping you as competent veterinariansto reach a diagnosis and formulate a treatment plan, your criticalacumen, examination, and communication skills remain themost crucial instruments for success in your daily practice.

52

The Pruritic Dog

Key Questions

All questions discussed in Section 1 (pages 2-10) may be rele-vant for a pruritic patient.

Differential Diagnoses If lesions are present, see page 58, The Dog with Papules,Pustules and Crusts. If no lesions are present, differential diag-noses are listed in Table 2-1.

53

54

Tab

le 2

-1D

iffe

ren

tial

Dia

gn

ose

s, C

om

mo

nly

Aff

ecte

d S

ites

, R

eco

mm

end

ed D

iag

no

stic

Tes

ts,

Trea

tmen

t O

pti

on

s, a

nd

Pro

gn

osi

s in

a P

ruri

tic

Do

g W

ith

ou

t Le

sio

ns

DIS

EA

SE

CO

MM

ON

LYA

FFEC

TED

SIT

ES

DIA

GN

OSTIC

TESTS

TR

EA

TM

EN

TP

RO

GN

OSIS

Ato

py*

(Hyp

erse

nsit

ivit

y to

air

born

e al

lerg

ens,

such

as p

olle

ns, h

ouse

dus

tm

ites

, or

mol

d sp

ores

)

Dia

gnos

is b

ased

on

hist

ory,

phys

ical

exa

min

atio

n, a

ndru

ling

out

diffe

rent

ial d

iag-

nose

s! I

ntra

derm

al s

kin

test

or s

erum

tes

t fo

r al

lerg

en-

spec

ific

IgE

(p. 4

2) id

enti

fyof

fend

ing

alle

rgen

s an

dal

low

form

ulat

ion

ofim

mun

othe

rapy

Alle

rgen

-spe

cific

imm

unot

hera

py (

p. 1

23),

anti

hist

amin

es (

p. 1

25),

esse

ntia

l fat

ty a

cids

(p

. 128

), g

luco

cort

icoi

ds

(p. 1

29),

sha

mpo

os (

p. 1

15)

Goo

d fo

r w

ell-

bein

gof

the

pat

ient

wit

hco

ntin

ued,

som

etim

esin

tens

ive

man

age-

men

t; g

uard

ed o

ut-

look

for

cure

Ant

ipar

asit

ic a

gent

s su

ch

as a

mit

raz,

lim

e su

lfur,

iver

-m

ecti

n, o

r m

ilbem

ycin

oxim

e (p

. 133

)

Avo

idan

ce, a

ntih

ista

min

es(p

. 125

.), e

ssen

tial

fatt

yac

ids

(p. 1

28),

gl

ucoc

orti

coid

s (p

. 129

),sh

ampo

os (

p. 1

15)

Exce

llent

, if o

ffend

ing

prot

ein(

s) is

(ar

e)id

enti

fied

and

avoi

d-ed

, oth

erw

ise

fair

wit

hco

ntin

ued

man

age-

men

t. P

oor

chan

ce

of c

ure

Ant

ifung

al a

gent

s su

ch a

ske

toco

nazo

le (

p. 1

31)

Goo

d, b

ut r

elap

se

likel

y if

prim

ary

dise

ase

not

addr

esse

d

Exce

llent

Scab

ies (

a hi

ghly

con

ta-

giou

s dise

ase

caus

ed b

ySa

rcop

tes s

cabi

ei va

r. ca

nis)

Mal

asse

zia

derm

atit

is (

anin

fect

ion

wit

h M

alas

sezi

apa

chyd

erm

atis

seco

ndar

y to

othe

r sk

in d

isor

ders

, suc

has

alle

rgie

s or

end

ocri

nepr

oble

ms)

Food

adv

erse

rea

ctio

n(m

ay o

r m

ay n

ot b

e al

ler-

gic,

com

mon

ly a

rea

ctio

nag

ains

t a

prot

ein,

rar

ely

an a

ddit

ive,

clin

ical

lyin

dist

ingu

isha

ble

from

atop

y)

Elim

inat

ion

diet

(p

. 46)

Face

, fee

t, ax

illae

, ear

s, ve

ntru

m, a

nd p

eria

nal a

rea

(Fig

ures

2-1

, 2-2

, and

2-3

).

Pinn

ae, e

lbow

s, ve

ntru

m,

hock

s (F

igur

es. 2

-4 a

nd 2

-5).

Face

, fee

t, ea

rs, v

entr

al n

eck,

vent

rum

, and

per

iana

l are

a(F

igur

es 2

-6 a

nd 2

-7)

Face

, fee

t, ax

illae

, ear

s, ve

ntru

m, p

eria

nal a

rea

(Fig

ure

2-8)

Cyt

olog

y (p

. 21)

Supe

rfic

ial s

kin

scra

ping

s (p

. 26)

, Sar

copt

es tr

eatm

ent

tria

l (p.

49)

.

55

Figu

re 2

-1Fa

cial

ery

them

a an

dal

opec

ia in

a 5

-yea

r-ol

dm

ale

cast

rate

d S

har

-pei

wit

h a

topi

c de

rmat

itis

.

Figu

re 2

-2P

eria

nal

alo

peci

a,

eryt

hem

a, a

nd

saliv

ary

stai

nin

g in

an

ato

pic,

2-

year

-old

, fem

ale

toy

Poo

dle.

Figu

re 2

-3P

odod

erm

atit

is in

a

1-ye

ar-o

ld, c

astr

ated

Gol

den

Ret

riev

er w

ith

atop

y.

Figu

re 2

-4S

ever

e pi

nn

al c

rust

ing

in a

10-

mon

th-o

ld,

fem

ale

Aki

ta w

ith

sc

abie

s.

56

Figure 2-5Ventral erythema, alopecia, and papulesin the dog seen in Figure 2-4.

Figure 2-6Hyperpigmentation and alopecia in a 2-year-old, spayed German Shepherdwith Malassezia canis. (Courtesy of Dr.Thiery Olivry.)

Figure 2-7Malassezia-related dermatitis in a 9-year-old, male British Bulldog (Courtesy ofDr. Michael Shipstone.)

Figure 2-8Pedal salivary staining in an 8-year-old,spayed Schnauzer with food-adversereaction. (Courtesy of Dr. Peter Ihrke.)

57

Atopy

Atopy

Food rechallenge

Adverse food reaction Scabies, Atopy out of season

Scabies treatment trial (p. 49)Elimination diet (p. 46)

Sequential rechallenge

Avoidance

Scabies

Skin test

Cytology

Scabies, Atopy, Adverse food reaction Malassezia dermatitis

- +

Antifungal therapy

No response Good response

Relapse No relapse

Monitoring

Relapse Remission for >12 months

(p.21)

Figure 2-9The Nonlesional Pruritic Dog

58

The Dog with Papules,Pustules, and Crusts

Key Questions

✓ What is the breed of this patient? (p. 2)

✓ How old was this patient when clinical signs were first recognized? (p. 3)

✓ How long has the disease been present and how did it progress? (p. 3)

✓ On which part of the body did the problem start? (p. 4)

✓ Is the animal itchy? (p. 5)

✓ Is the disease seasonal? (p. 6)

✓ Are there other clinical signs, such as sneezing, coughing, or diarrhea? (p. 7)

✓ What do you feed the animal? Was a special diet used in the past? (p. 7)

✓ Are there any other animals in the household? (p. 8)

✓ Does anybody in the household have skin disease? (p. 8)

✓ Was the disease treated before? If so, which drugs were used and how successful was treatment? (p. 8)

✓ What is used for flea control currently? (p. 9)

✓ When was the last medication given? (p. 9)

Differential Diagnoses Papules may develop into pustules and crusts, and any dog with anacute papular rash may eventually show pustules or crusts. Some dis-eases are characterized by papules that do not typically develop fur-ther into pustules (such as flea-bite hypersensitivity); other diseasestypically show crusting as their predominant symptom (such as zinc-responsive dermatitis). Tables 2-2, 2-3, and 2-4 list the major differ-ential diagnoses for dogs with papules, pustules, and crusts. Lesionsmay be follicular or nonfollicular (Figure 2-10). Follicular papulesand pustules indicate a pathologic process concentrating on the hairfollicle, most commonly bacterial folliculitis, demodicosis, or dermato-

59

Nonfollicular papule and pustule

Follicular papule and pustule

Figure 2-10

phytosis. Nonfollicular lesions may indicate pathologic processesconcentrating on the epidermis, dermis, or dermo-epidermal junction,such as superficial spreading pyoderma, flea-bite, contact hypersensi-tivity, or immune-mediated skin diseases. Be aware that some nonfol-licular processes may occasionally involve hair follicles as well.

60

Tab

le 2

-2D

iffe

ren

tial

Dia

gn

ose

s, C

om

mo

nly

Aff

ecte

d S

ites

, R

eco

mm

end

ed D

iag

no

stic

Tes

ts,

Trea

tmen

t O

pti

on

s, a

nd

Pro

gn

osi

s in

a D

og

wit

h P

apu

les

DIS

EA

SE

CO

MM

ON

LYA

FFEC

TED

SIT

ES

DIA

GN

OSTIC

TESTS

TR

EA

TM

EN

TP

RO

GN

OSIS

Flea

-bit

e hy

pers

ensi

tivi

ty(a

ntig

ens

in fl

ea s

aliv

ain

ject

ed d

urin

g th

e fle

a-bi

te c

ause

an

alle

rgic

reac

tion

in s

ensi

tize

ddo

gs)

Flea

con

trol

tria

l (p.

48)

isbe

st, s

erum

or s

kin

test

ing

for a

llerg

en-s

peci

fic Ig

E(o

nly

diag

nost

ic in

pre

senc

eof

type

I hy

pers

ensit

ivity

,do

gs w

ith d

elay

ed h

yper

sen-

sitiv

ity to

flea

ant

igen

s pro

-vi

de n

egat

ive

resu

lts to

seru

m te

sts,

p. 4

2.)

Flea

con

trol

(p.

136

),an

tipr

urit

ic t

hera

py (

p. 1

23)

Fair

to

exce

llent

depe

ndin

g on

clim

ate

and

owne

r co

mm

it-

men

t

Ant

ibac

teri

al t

reat

men

t (p

. 118

), s

ham

poo

ther

apy

(p. 1

15)

Loca

lized

form

: 95%

reso

lve

spon

tane

ousl

y, t

hus

beni

gn n

egle

ct o

r an

tim

i-cr

obia

l tre

atm

ent

only

(p

. 119

). G

ener

aliz

ed fo

rm:

Am

itra

z, iv

erm

ecti

n,m

ilbem

ycin

(p.

133

), a

nti-

bact

eria

l tre

atm

ent

for

sec-

onda

ry in

fect

ion

(p. 1

18)

Fair

Goo

d, if

und

erly

ing

dise

ase

can

be id

enti

-fie

d an

d tr

eate

dap

prop

riat

ely.

Rel

apse

likel

y, if

thi

s is

not

poss

ible

Bac

teria

l inf

ectio

n (t

ypi-

cally

by

Stap

hylo

cocc

usin

term

ediu

sand

typi

cally

seco

ndar

y to

an

unde

rly-

ing

dise

ase)

Dem

odic

osis

(pro

babl

y a

here

dita

ry sp

ecifi

c T-

cell

defe

ct th

at p

erm

its a

bnor

-m

al p

rolif

erat

ion

ofD

emod

ex c

anis,

a n

orm

alco

mm

ensa

l mite

of c

anin

esk

in. T

his p

rolif

erat

ion

lead

s to

a fu

rthe

r par

asite

-in

duce

d im

mun

osup

pres

-sio

n. A

dult-

onse

t dem

odi-

cosis

freq

uent

ly se

cond

ary

to h

orm

onal

dise

ases

, neo

-pl

asia

, ste

roid

s, or

oth

erch

emot

hera

py.)

Dor

sal l

umbo

sacr

al a

rea,

caud

omed

ial t

high

s, in

guin

alar

ea, v

entr

um, a

nd p

eriu

m-

bilic

al a

rea

(Fig

ures

2-1

1 an

d2-

12)

Eryt

hem

a, s

calin

g, s

ebor

rhea

,al

opec

ia, p

apul

es, p

ustu

les,

and

crus

ts, e

ithe

r fo

cal o

rge

nera

lized

dep

endi

ng o

nun

derl

ying

dis

ease

(Fi

gure

s 2-

13 a

nd 2

-14)

Loca

lized

form

: Foc

al e

ryth

e-m

a, a

lope

cia

and

scal

ing,

mos

tco

mm

only

on

the

face

(<

4sit

es).

Gen

eral

ized

form

:Er

ythe

ma,

alo

peci

a, p

apul

es,

plaq

ues,

pust

ules

and

cru

sts

whe

re la

rge

area

s, m

ore

than

5ar

eas,

or p

aws a

re in

volv

ed(F

igur

es 2

-15,

2-1

6, a

nd

2-17

)

Dee

p sk

in s

crap

ings

(p.

28)

,ha

ir p

luck

s (p

. 36)

, bio

psy

(p. 3

8)

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8)

Der

mat

ophy

tosi

s (d

er-

mat

ophy

tes

are

tran

s-m

itte

d by

con

tact

wit

hfu

ngal

ele

men

ts)

Woo

d’s l

amp

(p. 3

0), t

ri-ch

ogra

m (

p. 3

6), f

unga

l cul

-tu

re (

p. 3

2), b

iops

y (p

. 38)

Ant

imyc

otic

age

nts

such

as

gris

eofu

lvin

or

keto

cona

zole

(p. 1

31).

Top

ical

ant

ifung

alsh

ampo

os m

ay d

ecre

ase

cont

amin

atio

n of

env

iron

-m

ent

(p. 1

15).

Goo

d

Avo

idan

ce, w

hole

-bod

y su

its,

pent

oxyp

hylli

ne a

t 15

mg/

kgtw

ice

daily

, glu

coco

rtic

oids

(p. 1

29).

Surg

ical

exc

isio

n, st

erile

wat

er in

ject

ion,

glu

coco

rti-

coid

s (p.

129

), c

hem

othe

ra-

py, r

adia

tion

.

Gua

rded

Exce

llent

wit

h id

enti

-fic

atio

n an

d av

oida

nce

of a

llerg

en, f

air

wit

hm

edic

al m

anag

emen

t

Con

tact

hyp

erse

nsiti

vity

(del

ayed

hyp

erse

nsiti

vity

reac

tion

to e

nviro

nmen

tal

alle

rgen

s, cl

inic

ally

ove

r-la

ppin

g w

ith c

onta

ct ir

ri-ta

nt d

erm

atiti

s)

Mas

t cel

l tum

or*

Face

, pin

nae,

paw

s (F

igur

e 2-

18)

Eryt

hem

a, m

acul

es, p

apul

esan

d/or

ves

icle

s in

hai

rles

s or

spar

sely

hai

red

area

s (s

crot

um,

chin

, per

ineu

m, p

alm

ar/p

lant

arin

terd

igit

al s

kin,

ven

tral

abdo

men

) (F

igur

e 2-

19)

Mos

t com

mon

ly o

n th

e ca

udal

half

of th

e bo

dy (

Figu

re 2

-20)

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8)

Woo

d’s l

amp

(p. 3

0), t

ri-ch

ogra

m (

p. 3

6), f

unga

l cul

-tu

re (

p. 3

2), b

iops

y (p

. 38)

,pa

tch

test

ing

(p. 4

4)

Ant

ipar

asit

ic a

gent

s (p

. 133

)Ex

celle

ntSc

abie

s (a

high

ly c

onta

-gi

ous d

iseas

e ca

used

by

Sarc

opte

s sca

biei

var.

cani

s)

Supe

rfici

al sk

in sc

rapi

ngs

(p. 2

6), S

arco

ptes

trea

tmen

ttr

ial (

p. 4

9)

Pinn

ae, e

lbow

s, ve

ntru

m,

and

hock

s

61

Figu

re 2

-11

Alo

peci

a, l

ich

enif

ica-

tion

, fo

cal

ulce

rati

on,

and

crus

tin

g of

th

eta

ilba

se i

n a

n 1

1-ye

ar-

old,

spa

yed

Lab

rado

rR

etri

ever

mix

ed b

reed

wit

h f

lea-

bite

hyp

er-

sen

siti

vity

.

Figu

re 2

-12

Alo

peci

a an

d li

chen

ifi-

cati

on o

n t

he

tail

bas

e of

a 1-

year

-old

, mal

e L

has

aA

pso

cros

s w

ith

fle

a-bi

teh

yper

sen

siti

vity

.

62

Figu

re 2

-13

Pap

ules

, pla

ques

, an

dep

ider

mal

col

lare

ttes

in

a 6

-yea

r-ol

d, c

astr

ated

Bor

der

Col

lie w

ith

py

oder

ma.

Figu

re 2

-14

Cru

sted

pap

ules

in a

3-

year

-old

, mal

e ca

stra

ted

Lab

rado

r R

etri

ever

wit

hba

cter

ial p

yode

rma.

Figu

re 2

-15

Pap

ules

, pla

ques

, an

dcr

usts

in a

4-y

ear-

old

fem

ale

Box

er w

ith

ge

ner

aliz

ed d

emod

icos

is.

Figu

re 2

-16

Sev

ere

podo

derm

atit

isin

a 1

-yea

r-ol

d, c

astr

ated

Rot

twei

ler

wit

h g

ener

al-

ized

dem

odic

osis

.

63

Figu

re 2

-17

Abd

omin

al p

apul

es

in a

4-y

ear-

old,

spa

yed

Ter

rier

mix

ed b

reed

wit

h g

ener

aliz

edde

mod

icos

is.

Figu

re 2

-18

Sev

ere

crus

tin

g on

th

eh

ead

of a

10-

year

-old

, cas

-tr

ated

Bea

gle

mix

ed b

reed

wit

h d

erm

atop

hyt

osis

caus

ed b

y T

rich

ophy

ton

men

tagr

ophy

tes.

Not

e th

esh

arp

dem

arca

tion

bet

wee

naf

fect

ed a

nd

non

affe

cted

skin

fre

quen

tly

seen

wit

hT

rich

ophy

ton

infe

ctio

ns.

Figu

re 2

-19

Pap

ules

an

d pl

aque

sre

sult

ing

from

con

tact

hyp

erse

nsi

tivi

ty in

a

3-ye

ar-

old

mal

eW

eim

aran

er. (

Cou

rtes

yof

Dr.

Son

ya B

ette

nay

.)

Figu

re 2

-20

Mas

t-ce

ll tu

mor

in a

5-

year

-old

, cas

trat

edL

abra

dor

Ret

riev

er.

64

Flea

-bit

e hy

pers

ensi

tivi

ty(a

ntig

ens

in fl

ea s

aliv

ain

ject

ed d

urin

g th

e fle

a-bi

te c

ause

an

alle

rgic

rea

c-ti

on in

sen

siti

zed

dogs

)

Flea

con

trol

tria

l (p.

48)

isbe

st, s

erum

or s

kin

test

ing

for a

llerg

en-s

peci

fic Ig

E(o

nly

diag

nost

ic in

pre

senc

eof

type

I hy

pers

ensit

ivity

,do

gs w

ith d

elay

ed h

yper

sen-

sitiv

ity to

flea

ant

igen

s pro

-vi

de n

egat

ive

resu

lts to

seru

m te

sts (

p. 1

23)

Flea

con

trol

(p.

136

),an

tipr

urit

ic t

hera

py

(p. 1

23)

Fair

to

exce

llent

depe

ndin

g on

clim

ate

and

owne

r co

mm

it-

men

t

Ant

ibac

teri

al t

reat

men

t (p

. 118

), s

ham

poo

ther

apy

(p. 1

15)

Goo

d, if

und

erly

ing

dise

ase

can

be id

enti

-fie

d an

d tr

eate

d ap

pro-

pria

tely

. Rel

apse

like

ly,

if th

is is

not

pos

sibl

e

Bac

teri

al in

fect

ion

(typ

i-ca

lly b

y St

aphy

loco

ccus

inte

rmed

ius

and

typi

cally

seco

ndar

y to

an

unde

rly-

ing

dise

ase)

Dor

sal l

umbo

sacr

al a

rea,

cau

-do

med

ial t

high

s, in

guin

al a

rea,

vent

rum

, and

per

ium

bilic

alar

ea (

Figu

res 2

-11

and

2-12

)

Eryt

hem

a, s

calin

g, s

ebor

rhea

,al

opec

ia, p

apul

es, p

ustu

les,

and

crus

ts, e

ithe

r fo

cal o

rge

nera

lized

dep

endi

ng o

nun

derl

ying

dis

ease

(Fi

gure

s 2-

13, 2

-14,

and

2-1

5)

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8)

Figu

re 2

-21

Pap

ules

, pus

tule

s, a

nd

crus

tin

g in

a 6

-yea

r-ol

d, c

astr

ated

Lab

rado

rw

ith

sev

ere

pem

phig

usfo

liac

eus.

Figu

re 2

-22

Foot

pad

hyp

erke

rato

sis

in a

13-

year

-old

, spa

yed

Aus

tral

ian

Cat

tled

ogw

ith

pem

phig

us f

oli-

aceu

s.

Loca

lized

form

: 95%

reso

lve

spon

tane

ously

, thu

s ben

ign

negl

ect o

r ant

imic

robi

altr

eatm

ent o

nly,

p. 1

31).

Fair

Loca

lized

form

: Foc

al e

ryth

e-m

a, a

lope

cia

and

scal

ing,

mos

tco

mm

only

on

the

face

(<

4sit

es).

Gen

eral

ized

form

:Er

ythe

ma,

alo

peci

a, p

apul

es,

Dee

p sk

in s

crap

ings

(p.

28)

,ha

ir p

luck

s (p

. 36)

, bio

psy

(p. 3

8)Tab

le 2

-3D

iffe

rent

ial D

iag

nose

s, C

omm

only

Aff

ecte

d S

ites

, Rec

omm

end

ed D

iag

nost

ic T

ests

, Tre

atm

ent

Op

tion

s,an

d P

rog

nosi

s in

a D

og w

ith

Pust

ules

DIS

EA

SE

CO

MM

ON

LYA

FFEC

TED

SIT

ES

DIA

GN

OSTIC

TESTS

TR

EA

TM

EN

TP

RO

GN

OSIS

Dem

odic

osis

(pro

babl

y a

here

dita

ry sp

ecifi

c T-

cell

defe

ct th

at p

erm

its a

bnor

-m

al p

rolif

erat

ion

ofD

emod

ex c

anis,

a n

orm

alco

mm

ensa

l mite

of c

anin

esk

in. T

his p

rolif

erat

ion

Imm

unos

uppr

essi

on

(p. 1

41)

Fair

wit

h ap

prop

riat

etr

eatm

ent,

poo

r fo

rcu

re (

exce

pt d

rug-

trig

-ge

red

pem

phig

us)

Pem

phig

us fo

liace

us*

(im

mun

e-m

edia

ted

skin

dise

ase

char

acte

rized

by

intr

aepi

derm

al p

ustu

le fo

r-m

atio

n du

e to

pem

phig

usan

tibod

ies a

gain

st a

ntig

ens

in th

e in

terc

ellu

lar c

on-

nect

ions

. May

be

idio

-pa

thic

dru

g-in

duce

d or

para

neop

last

ic)

Plan

um n

asal

e, p

erio

cula

rar

ea, l

ips,

dors

al m

uzzl

e, in

ner

surf

ace

of p

inna

e, fo

ot p

ads,

claw

fold

s, ni

pple

s (i

n ca

ts)

(Fig

ure

2-21

, 2-2

2, 2

-23,

2-4

3)

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8)

65

Figu

re 2

-23

Lar

ge p

ustu

les

in a

2-

year

-old

, cas

trat

edC

how

Ch

ow w

ith

pem

phig

us f

olia

ceus

(Cou

rtes

y of

Dr.

Th

ierr

y O

livr

y).

Figu

re 2

-25

Per

iocu

lar

eryt

hem

a,al

opec

ia,

and

crus

tin

gin

a 4

-yea

r-ol

d, f

emal

eH

usky

wit

h z

inc-

resp

onsi

ve d

erm

atos

is(C

ourt

esy

of D

r. S

onya

Bet

ten

ay).

Figu

re 2

-24

Foot

-pad

hyp

erke

rato

sis

and

crus

tin

g in

a 9

-yea

r-ol

d, s

paye

d G

erm

anS

hep

her

d w

ith

met

abol

-ic

epi

derm

al n

ecro

sis

(Cou

rtes

y of

Dr.

Mic

hae

l Sh

ipst

one)

.

Gen

eral

ized

form

: Am

itraz

,iv

erm

ectin

, milb

emyc

in

(p. 1

33),

ant

ibac

teria

l tre

at-

men

t for

seco

ndar

y in

fect

ion

(p. 1

18)

lead

s to

a fu

rthe

r par

asite

-in

duce

d im

mun

osup

pres

-sio

n. A

dult-

onse

t dem

odi-

cosis

freq

uent

ly se

cond

ary

to h

orm

onal

dise

ases

, neo

-pl

asia

, ste

roid

s, or

oth

erch

emot

hera

py.)

plaq

ues,

pust

ules

and

cru

sts

whe

re la

rge

area

s, m

ore

than

5ar

eas,

or p

aws a

re in

volv

ed(F

igur

es 2

-15,

2-1

6, a

nd 2

-17)

66

Tab

le 2

-4D

iffe

ren

tial

Dia

gn

ose

s, C

om

mo

nly

Aff

ecte

d S

ites

, R

eco

mm

end

ed D

iag

no

stic

Tes

ts,

Trea

tmen

t O

pti

on

s, a

nd

Pro

gn

osi

s in

a D

og

wit

h C

rust

sD

ISEA

SE

CO

MM

ON

LYA

FFEC

TED

SIT

ES

DIA

GN

OSTIC

TESTS

TR

EA

TM

EN

TP

RO

GN

OSIS

Flea

con

trol

(p.

136

),an

tipr

urit

ic

ther

apy

(p. 1

23)

Ant

ipar

asit

ic a

gent

s (p

. 133

)Ex

celle

nt

Loca

lized

form

: 95%

reso

lve

spon

tane

ously

, thu

s ben

ign

negl

ect o

r ant

imic

robi

altr

eatm

ent o

nly,

p. 1

31).

Gen

eral

ized

form

: Am

itraz

,iv

erm

ectin

, milb

emyc

in

(p. 1

33),

ant

ibac

teria

l tre

at-

men

t for

seco

ndar

y in

fect

ion

(p. 1

18)

Fair

Fair

to

exce

llent

depe

ndin

g on

clim

ate

and

owne

r co

mm

it-

men

t

Bac

teri

al in

fect

ion

Flea

-bite

hyp

erse

nsiti

vity

(a

ntig

ens i

n fle

a sa

liva

inje

cted

dur

ing

the

flea

bite

cau

se a

n al

lerg

ic re

ac-

tion

in se

nsiti

zed

dogs

)

Dem

odic

osis

(pro

babl

y a

here

dita

ry sp

ecifi

c T-

cell

defe

ct th

at p

erm

its a

bnor

-m

al p

rolif

erat

ion

ofD

emod

ex c

anis,

a n

orm

alco

mm

ensa

l mite

of c

anin

esk

in. T

his p

rolif

erat

ion

lead

s to

a fu

rthe

r par

asite

-in

duce

d im

mun

osup

pres

-sio

n. A

dult-

onse

t dem

odi-

cosis

freq

uent

ly se

cond

ary

to h

orm

onal

dise

ases

, neo

-pl

asia

, ste

roid

s, or

oth

erch

emot

hera

py.)

Scab

ies

(a h

ighl

y co

nta-

giou

s dise

ase

caus

ed b

ySa

rcop

tes s

cabi

ei va

r. ca

nis)

Supe

rfici

al sk

in sc

rapi

ngs

(p. 2

6), S

arco

ptes

trea

tmen

ttr

ial (

p. 4

9)

Dor

sal l

umbo

sacr

al a

rea,

cau

-do

med

ial t

high

s, in

guin

alar

ea, v

entr

um, p

eriu

mbi

lical

area

(se

e Fi

gure

s 2-

11 a

nd

2-12

.)

Loca

lized

form

: Foc

al e

ryth

e-m

a, a

lope

cia

and

scal

ing,

mos

tco

mm

only

on

the

face

(<

4sit

es).

Gen

eral

ized

form

:Er

ythe

ma,

alo

peci

a, p

apul

es,

plaq

ues,

pust

ules

and

cru

sts

whe

re la

rge

area

s, m

ore

than

5ar

eas,

or p

aws a

re in

volv

ed(F

igur

es 2

-15,

2-1

6, a

nd 2

-17)

Pinn

ae, e

lbow

s, ve

ntru

m,

and

hock

s

Imm

unos

uppr

essi

on

(p. 1

41)

Fair

wit

h ap

prop

riat

etr

eatm

ent,

poo

r fo

rcu

re (

exce

pt d

rug-

trig

-ge

red

pem

phig

us)

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8)Pl

anum

nas

ale,

per

iocu

lar

area

, lip

s, do

rsal

muz

zle,

inne

rsu

rfac

e of

pin

nae,

foot

pad

s,cl

aw fo

lds,

nipp

les

(in

cats

)(F

igur

e 2-

21, 2

-22,

2-2

3, 2

-43)

Dee

p sk

in s

crap

ings

(p.

28)

,ha

ir p

luck

s (p

. 36)

, bio

psy

(p. 3

8)

Inse

ct c

ontr

ol t

rial

(p.

48)

,se

rum

or

skin

tes

ting

for

alle

rgen

-spe

cific

IgE

(on

lydi

agno

stic

in p

rese

nce

ofty

pe I

hyp

erse

nsit

ivit

y, d

ogs

wit

h de

laye

d hy

pers

ensi

tivi

-ty

to

flea

anti

gens

are

neg

a-ti

ve o

n se

rum

tes

ts, p

. 42)

Pem

phig

us fo

liace

us*

(im

mun

e-m

edia

ted

skin

dise

ase

char

acte

rized

by

intr

aepi

derm

al p

ustu

lefo

rmat

ion

due

to p

emph

i-gu

s ant

ibod

ies a

gain

stan

tigen

s in

the

inte

rcel

l-ul

ar c

onne

ctio

ns. M

ay b

eid

iopa

thic

dru

g-in

duce

dor

par

aneo

plas

tic)

Ant

iseb

orrh

eic

sham

poos

(p. 1

15),

moi

stur

izer

s,re

tino

ids,

cor

tico

ster

oids

(p

. 129

)

Vit

amin

E (

200-

800

iu/d

ay),

pent

oxyp

hylli

ne (

20 m

g/kg

q 12

h),

for

acut

e fla

res

pred

niso

lone

(1-

2 m

g/kg

q24

h)

Goo

d to

gua

rded

for

wel

l-be

ing,

poo

r fo

rcu

re.

Var

ies

Dog

s ty

pica

lly w

ill n

otde

teri

orat

e fu

rthe

raf

ter

1 ye

ar o

f age

.

Idio

path

ic se

borr

hea*

(prim

ary

kera

tiniza

tion

defe

ct a

s aut

osom

al re

ces-

sive

trai

t with

dec

reas

edep

ider

mal

cel

l ren

ewal

time

and

thus

hyp

erpr

olif-

erat

ion

of e

pide

rmis,

seba

-ce

ous g

land

s, an

d fo

llicu

-la

r inf

undi

bulu

m.

Seco

ndar

y to

infla

mm

a-tio

n, e

ndoc

rine

dise

ase,

or

nutr

ition

al d

efic

ienc

ies)

Der

mat

omyo

sitis

(aut

oso-

mal

dom

inan

t in

Col

lies

and

Shel

ties,

first

sign

s in

pupp

ies)

Eryt

hem

a, sc

alin

g al

opec

ia,

mild

cru

stin

g in

face

(pa

rtic

u-la

rly p

erio

cula

r are

a) e

artip

s,ca

rpal

and

tars

al re

gion

s, di

g-its

, tai

l tip

, myo

sitis,

and

inse

vere

cas

es, m

egas

opha

gus

Oti

tis

exte

rna,

dig

ital

hyp

er-

kera

tosi

s, dr

y fla

ky s

kin,

or

sebo

rrhe

ic d

erm

atit

is p

re-

dom

inan

tly

on fa

ce, f

eet,

vent

ral n

eck,

and

ven

tral

abdo

men

(Fi

gure

2-2

6)

Bio

psy

(p. 3

8)

Skin

bio

psy,

mus

cle

biop

sy,

EMG

Ant

imic

robi

al t

reat

men

t,vi

tam

in a

nd m

iner

al s

uppl

e-m

ent,

high

-qua

lity

prot

ein,

intr

aven

ous

amin

o ac

ids

Poor

Met

abol

ic e

pide

rmal

necr

osis

*(p

atho

gene

sis

uncl

ear)

Bio

psy

(p. 3

8)M

uzzl

e, m

ucoc

utan

eous

junc

-ti

ons,

dist

al li

mbs

, foo

t pa

ds,

elbo

ws,

hock

s, ve

ntru

m(F

igur

e 2-

24)

Ant

imyc

otic

age

nts

such

as

gris

eofu

lvin

or

keto

cona

zole

(p. 1

31).

Top

ical

ant

ifung

alsh

ampo

os m

ay d

ecre

ase

cont

amin

atio

n of

env

iron

-m

ent.

Goo

dD

erm

atop

hyto

sis

(der

-m

atop

hyte

s ar

e tr

ans-

mit

ted

by c

onta

ct w

ith

fung

al e

lem

ents

)

Woo

d’s l

amp

(p. 3

0), t

ri-ch

ogra

m (

p. 3

6), f

unga

l cul

-tu

re (

p. 3

2), b

iops

y (p

. 38)

Face

, pin

nae,

paw

s (F

igur

e 2-

18)

67

Zinc

-res

pons

ive

derm

atiti

s(Z

inc

defic

ienc

y du

e to

insu

ffici

ent z

inc

in th

edi

et o

r ins

uffic

ient

abs

orp-

tion

of zi

nc, e

spec

ially

inar

ctic

bre

eds)

Peri

ocul

ar, p

erio

ral,

pinn

ae,

chin

, foo

t pa

ds, p

lanu

mna

sale

, pre

ssur

e po

ints

(Fig

ure

2-25

)

Bio

psy

(p. 3

8)Zi

nc s

uppl

emen

tati

on, l

ow-

dose

glu

coco

rtic

oids

to

incr

ease

zin

c ab

sorp

tion

Fair

68

Dermatophytosis

Antifungaltherapy (p.130)

Cytology (p.21)Skin Scrapings (p.26)

Antibiotics(p.119)

Pyoderma Demodicosis or scabies with or without secondary infection

Wood's lamp (p.30)Fungal culture (p.32)

Insect bitetrial (p.48)

Scabies trial(p.49)

Biopsy(p.38)

See approach to nonlesional, pruritic dog (p.57)

Search for underlying causes (allergies, endocrine diseases)

Insufficientresponse

Lessions resolve,itch persists

Remission

Remission RemissionNo response No response

CytologySkin scrapings

-

-CytologySkin scrapings -

+

+

CytologySkin scrapings

- ++

Depending on clinical signs

Insect bite hypersensitivity Scabies

Figure 2-27The Dog with Papules, Pustules, or Crusts

Figure 2-26Crusted papules and plaques caused byidiopathic seborrhea in an 8-year-old,male castrated Cocker Spaniel.

The Dog with AlopeciaMany diseases are associated with alopecia in conjunction withpruritus and other lesions. Here we discuss dogs with clinicallynoninflammatory alopecias.

Key Questions

✓ What breed is the patient? (p. 2)

✓ How old was this patient when clinical signs were first recognized?(p. 3)

✓ How long has the disease been present and how did it progress? (p. 3)

✓ On which part of the body did the problem start? (p. 4)

✓ Is the animal itchy? (p. 5)

✓ Is the disease seasonal? (p. 6)

✓ Are there other animals in the household? (p. 5)

✓ Does anybody in the household have skin disease? (p. 8)

✓ Was the disease treated before? If so, which drugs were used andhow successful was treatment? (p. 8).

If the alopecic dog is pruritic but lacks other lesions, the approach isdifferent from that used in a bald dog without pruritus. Many alope-cias are characterized by dry skin and mild scaling, which may or maynot be pruritic. The use of moisturizers will help the dryness and mayaddress concurrent pruritus. If pruritus persists, then the approach isthe same as for the dog with pruritus without lesions (p. 54).Differential diagnoses for noninflammatory and nonpruritic alopeciasare outlined later in this section.

69

70

Tab

le 2

-5D

iffe

ren

tial

Dia

gn

ose

s, C

om

mo

nly

Aff

ecte

d S

ites

, R

eco

mm

end

ed D

iag

no

stic

Tes

ts,

Trea

tmen

t O

pti

on

s, a

nd

Pro

gn

osi

s in

Do

gs

wit

h N

on

infl

amm

ato

ry,

No

np

ruri

tic

Alo

pec

ia

DIS

EA

SE

CO

MM

ON

SYM

PTO

MS

DIA

GN

OSTIC

TESTS

TR

EA

TM

EN

TP

RO

GN

OSIS

Hyp

erad

reno

cort

icis

m*

(spo

ntan

eous

or

idio

path

-ic

) T

he s

pont

aneo

us fo

rmis

an

exce

ssiv

e pr

oduc

-ti

on o

f glu

coco

rtic

oids

due

eith

er t

o a

mic

road

e-no

ma

or m

acro

aden

oma

of t

he p

itui

tary

gla

nd –

pitu

itar

y-de

pend

ent

hype

radr

enoc

orti

cism

[=PD

H],

in 8

5% –

or

due

to a

dren

ocor

tica

l neo

-pl

asm

s in

15%

)

Seru

m b

ioch

emist

ry (

Seru

mal

kalin

e ph

osph

atas

e[S

AP]

↑, c

hole

ster

ol ↑

, ala

-ni

ne a

min

otra

nsfe

rase

[ALT

]↑,

glu

cose

↑, u

rea

↓),

hem

ogra

m (

leuk

ocyt

osis,

neut

roph

ilia,

lym

phop

enia

,an

d eo

sinop

enia

), u

rinal

ysis

(spe

cific

gra

vity

↓,

cort

isol:c

reat

inin

e ra

tio ↑

),ra

diog

raph

s (he

pato

meg

aly,

oste

opor

osis,

min

eral

izatio

nof

adr

enal

gla

nds)

, low

dos

ede

xam

etha

sone

supp

ress

ion

test

, adr

enoc

ortic

otro

pic

horm

one

(AC

TH

) in

PD

H↑,

ultr

ason

ogra

phy

(adr

enal

glan

d siz

e ↑)

, AC

TH

stim

u-la

tion

test

Iatr

ogen

ic fo

rm: C

auti

ousl

yta

per

and

then

dis

cont

inue

gluc

ocor

tico

id a

dmin

istr

a-ti

on.

Idio

path

ic fo

rm: o

,p´-

DD

D (

mit

otan

e), k

eto-

cona

zole

for

pitu

itar

y-de

pend

ent

hype

radr

enoc

or-

tici

sm (

p. 1

31),

sur

gica

lre

mov

al o

f affe

cted

gla

ndfo

r ad

reno

cort

ical

neo

plas

ia

App

roxi

mat

ely

60%

of d

ogs

wit

h ad

rena

ltu

mor

s w

ere

repo

rted

to s

urvi

ve a

dren

alec

-to

my

and

the

post

op-

erat

ive

peri

od. T

heav

erag

e lif

e ex

pect

an-

cy w

as 3

6 m

onth

s.A

dren

al a

deno

mas

have

a b

ette

r pr

ogno

-si

s th

an a

deno

carc

ino-

mas

. The

life

spa

n of

dogs

wit

h PD

H t

reat

-ed

med

ical

ly a

vera

ged

30 m

onth

s w

ith

som

edo

gs li

ving

long

erth

an 1

0 ye

ars

and

othe

rs o

nly

days

.

Hor

mon

e re

plac

emen

tth

erap

y w

ith

levo

thyr

oxin

e(p

. 144

).

Goo

d, a

ltho

ugh

not

all p

atie

nts

stay

inco

mpl

ete

and

con-

stan

t re

mis

sion

desp

ite

adeq

uate

su

pple

men

tati

on

Hyp

othy

roid

ism(l

ymph

ocyt

ic th

yroi

ditis

[pre

sum

ably

aut

oim

mun

e]or

idio

path

ic th

yroi

dne

cros

is w

hich

may

be

end-

stag

e ly

mph

ocyt

ic

thyr

oidi

tis)

Poly

uria

, pol

ydip

sia,

pol

ypha

-gi

a, d

ull h

airc

oat,

slo

w h

air

grow

th, c

oat

colo

r ch

ange

,pa

rtia

l-to

-com

plet

e sy

mm

et-

ric

alop

ecia

of t

he r

ump,

thi

nsk

in, r

ecur

rent

ski

n an

d bl

ad-

der

infe

ctio

ns, e

xerc

ise

into

l-er

ance

, pan

ting

, mus

cle

atro

-ph

y, a

nest

rus,

cal

cino

sis

cuti

s(F

igur

e 2-

28),

beh

avio

ral

chan

ges,

and

neu

rolo

gic

sign

s (t

he la

tter

wit

h a

pitu

-it

ary

mac

road

enom

a)

Leth

argy

, obe

sity

, dep

ress

ion,

dull

brit

tle

coat

, rec

urre

ntsk

in in

fect

ions

, thi

ck, p

uffy

skin

(m

yxed

ema)

, hyp

otri

-ch

osis

, alo

peci

a (f

rict

iona

lar

eas,

flank

s, tr

unk,

face

),hy

pert

rich

osis

(B

oxer

s), s

eb-

orrh

ea, n

euro

mus

cula

r sy

mp-

tom

s, in

fert

ility

Seru

m b

ioch

emis

try

(SA

P ↑,

chol

este

rol ↑

, ALT

↑),

hem

ogra

m (

anem

ia),

thyr

oid

test

s (fr

ee th

yrox

ine

[T4]

,to

tal T

4, fr

ee T

4 by

equ

ilib-

rium

dia

lysi

s, th

yroi

d st

imu-

lati

ng h

orm

one

(TSH

)as

says

, TSH

stim

ulat

ion

test

,th

yrot

ropi

ne-r

elea

sing

hor

-m

one

(TR

H)

stim

ulat

ion

test

)

Folli

cula

r dy

spla

sia

(unk

now

n et

iolo

gy)

Bio

psy

(p. 3

8), r

ulin

g ou

ten

docr

ine

diso

rder

s in

equi

voca

l cas

es.

Ret

inoi

ds, m

elat

onin

(p

. 144

)Ex

celle

nt fo

r w

ell-

bein

g, g

uard

ed fo

rha

ir r

egro

wth

Mel

aton

in (

p. 1

44)

Ret

inoi

ds, e

ssen

tial f

atty

aci

dsu

pple

men

tatio

n (p

. 128

).G

ood

for

wel

l-be

ing,

poor

for

hair

reg

row

th

Ben

ign

negl

ect

poss

ibly

inco

njun

ctio

n w

ith

moi

stur

-iz

ers.

Exce

llent

for

wel

l-be

ing,

poo

r fo

r ha

irre

grow

th

Exce

llent

for

gene

ral

wel

l-be

ing,

fair

for

prev

enti

on o

f hai

r lo

ssw

ith

trea

tmen

t

Cyc

lic fo

llicu

lar d

yspl

asia

(pos

sibly

rela

ted

to d

ura-

tion

of d

aily

ligh

t exp

o-su

re)

Patt

ern

bald

ness

(unk

now

n et

iolo

gy, p

rob-

ably

gen

etic

ally

det

er-

min

ed).

Dac

hshu

nds

and

Gre

yhou

nds

are

pred

is-

pose

d

Col

or d

iluti

on a

lope

cia

(gen

etic

ally

det

erm

ined

dege

nera

tive

pro

cess

resu

ltin

g in

ligh

ter

hair

colo

r w

ith

pigm

enta

rycl

umpi

ng a

nd d

amag

e to

the

hair

sha

ft a

nd b

ulb)

Cyt

olog

y (p

. 21)

, tr

icho

gram

(p.

36)

, ski

nsc

rapi

ngs

(p. 2

6), b

iops

y (p

. 38)

.

Non

infla

mm

ator

y al

opec

iasp

arin

g th

e he

ad a

nd li

mbs

(Fig

ure

2-29

)

Seas

onal

loca

l hyp

erpi

gmen

ta-

tion

and

alo

peci

a of

the

tru

nk(o

ften

the

flan

ks)

wit

h in

itia

llysp

onta

neou

s re

grow

th a

fter

3to

4 m

onth

s (F

igur

e 2-

30)

Alo

peci

a of

pin

nae,

pos

taur

ic-

ular

reg

ion,

ven

tral

nec

k, v

en-

trum

, cau

dom

edia

l thi

ghs,

tail

(Fig

ure

2-31

)

Alo

peci

a of

dilu

te b

lue

or fa

wn

colo

red

area

s, of

ten

wit

h sc

ali-

ness

and

rec

urre

nt fo

llicu

litis

(Fig

ure

2-32

)

Ben

ign

negl

ect

in c

onju

nc-

tion

wit

h m

oist

uriz

ers

and

poss

ibly

ant

imic

robi

al t

reat

-m

ent,

neu

teri

ng in

inta

ctdo

gs, t

esto

ster

one

in c

as-

trat

ed m

ales

, est

roge

n in

spay

ed fe

mal

es, g

row

th h

or-

mon

e (d

iabe

toge

nic)

, o,p

’-D

DD

(ri

sk o

f hyp

oadr

eno-

cort

icis

m)

Goo

d fo

r w

ell-

bein

g,tr

eatm

ent

usua

lly o

nly

lead

s to

tem

pora

ryre

mis

sion

Gro

wth

hor

mon

e-re

spon

-siv

e de

rmat

osis,

est

roge

n-re

spon

sive

derm

atos

is, c

as-

trat

ion-

resp

onsiv

e de

r-m

atos

is, a

dren

al se

x ho

r-m

one

imba

lanc

e, te

stos

-te

rone

-res

pons

ive

der-

mat

osis,

hyp

ogon

adism

(unc

lear

etio

logy

in m

ost

of th

ese

synd

rom

es th

atm

ay b

e gr

oupe

d to

geth

eras

“al

opec

ia x

”)

Bio

psy

(p. 3

8) in

con

junc

-tio

n w

ith ru

ling

out o

ther

endo

crin

e di

sord

ers,

such

as

hype

radr

enoc

ortic

ism a

ndhy

poth

yroi

dism

, tha

t may

have

sim

ilar h

istop

atho

logi

cch

ange

s.

Pupp

y-lik

e ha

ir c

oat,

coat

col

orch

ange

s, hy

potr

icho

sis

and

alop

ecia

of t

he p

erin

eal a

ndge

nita

l reg

ion,

flan

k, t

runk

,ne

ck (

Figu

res

2-33

and

2-3

4)

Bio

psy

(p. 3

8), l

ack

ofen

docr

ine

abno

rmal

itie

s.

Bio

psy

(p. 3

8)

71

72

DIS

EA

SE

CO

MM

ON

LYA

FFEC

TED

SIT

ES

DIA

GN

OSTIC

TESTS

TR

EA

TM

EN

TP

RO

GN

OSIS

Sert

oli’s

cel

l tum

or(m

ost

com

mon

in c

ryp-

torc

hid

test

icle

s, in

crea

sed

leve

ls o

f est

roge

n)

Blo

od e

stro

gen

↑, s

kin

biop

sy (

p. 3

8), h

isto

path

o-lo

gic

eval

uati

on o

f rem

oved

test

es

Cas

trat

ion

Exce

llent

wit

h no

met

asta

ses,

gua

rded

wit

h m

etas

tase

s or

apla

stic

ane

mia

Ova

rioh

yste

rect

omy

Not

nee

ded,

if s

tres

s w

as a

one-

tim

e ev

ent

Exce

llent

Add

ress

ing

the

unde

rlyi

ngca

use

Exce

llent

if c

ausa

tive

fact

or is

add

ress

ed

succ

essf

ully

Exce

llent

Hyp

eres

trog

enism

(C

ystic

ova

ries o

r fun

c-tio

nal o

varia

n tu

mor

s)

Ana

gen

deflu

xion

(se

vere

syst

emic

dise

ases

or a

nti-

mito

tic d

rugs

inte

rfere

with

hai

r gro

wth

, res

ultin

gin

abn

orm

al h

air s

hafts

,ha

ir br

eaks

off

sudd

enly

)

Telo

gen

efflu

vium

(sev

ere

stre

ss [e

.g. s

hock

,fe

ver,

surg

ery]

cau

ses

abru

pt c

essa

tion

of h

air

grow

th a

nd s

wit

chin

g to

cata

gen

and

then

tel

ogen

in m

any

folli

cles

, whi

char

e al

l she

d si

mul

tane

-ou

sly

1 to

3 m

onth

s af

ter

the

insu

lt)

Hist

ory,

tric

hogr

am (

p. 3

6).

Bila

tera

lly s

ymm

etri

c al

ope-

cia

of w

ear

area

s su

ch a

s co

l-la

r re

gion

, rum

p, p

erin

eum

and

geni

tal a

rea,

gyn

ecom

as-

tia,

pen

dulo

us p

repu

ce,

attr

acti

on o

f mal

e do

gs, l

in-

ear

prep

utia

l der

mat

osis

,pr

osta

tom

egal

y, p

rost

atit

is,

estr

ogen

-ind

uced

bon

e m

ar-

row

sup

pres

sion

Bila

tera

lly s

ymm

etri

c al

ope-

cia

of p

erin

eum

, ing

uina

l are

aan

d fla

nks,

gyne

com

asti

a,an

d co

med

ones

, est

rus

cycl

eab

norm

alit

ies

Alo

peci

a of

sud

den

onse

t

Foca

l to

gene

raliz

ed a

lope

cia

of s

udde

n on

set

His

tory

, tri

chog

ram

(p.

36)

Bio

psy

(p. 3

8), b

lood

est

ro-

gen

↑, u

ltra

sono

grap

hy,

lapa

rasc

opy

Tab

le 2

-5 c

on

tin

ued

Post

-clip

ping

Alo

peci

a(a

rcti

c or

plu

shco

ated

bree

ds fa

il to

reg

row

hai

rin

clip

ped

area

s; ca

use

isun

know

n)

Dia

gnos

is b

ased

on

sign

al-

men

t, hi

stor

y, a

nd p

rese

nce

of n

onin

flam

mat

ory

alop

e-ci

a in

clip

ped

area

s on

ly.

Non

e. H

air

will

gro

w b

ack

in 6

-24

mon

ths

Exce

llent

Clip

ped

area

s

73

Figu

re 2

-28

Pap

ules

an

d cr

usts

in

an

8-ye

ar-o

ld, m

ale

cas-

trat

ed B

ull

Ter

rier

wit

hca

lcin

osis

cut

is d

ue t

opi

tuit

ary-

depe

nde

nt

hyp

erad

ren

ocor

tici

sm

Figu

re 2

-30

Alo

peci

a an

d h

yper

pig-

men

tati

on i

n t

he

flan

kar

ea o

f a

6-ye

ar-o

ld,

mal

e ca

stra

ted

Box

erw

ith

cyc

lic

foll

icul

ardy

spla

sia.

Figu

re 2

-29

Alo

peci

a du

e to

folli

cula

rdy

spla

sia

in a

2-y

ear-

old,

fem

ale

Cur

ly-c

oate

dR

etri

ever

Figu

re 2

-31

Pat

tern

alo

peci

a.(C

ourt

esy

of D

r. P

eter

Ihrk

e.)

74

Figu

re 2

-32

Col

or d

iluti

on a

lope

cia

in a

3-y

ear-

old,

fem

ale

York

shir

e T

erri

er.

(Cou

rtes

y of

Dr.

Th

ierr

yO

livry

.)

Figu

re 2

-34

Cas

trat

ion

-res

pon

sive

derm

atos

is i

n a

5-y

ear-

old

mal

e K

eesh

ond.

(Cou

rtes

y of

Dr.

Son

yaB

ette

nay

.)

Figu

re 2

-33

Gro

wth

hor

mon

e-re

spon

sive

der

mat

osis

ina

9-ye

ar-o

ld, s

paye

dK

eesh

ond.

75

His

tory

(p.2

)

Dem

odic

osis

Der

mat

ophy

tosi

s

Inse

ct b

ite

tria

l (p.

xxx)

Inse

ct b

ite

tria

l (p.

xxx)

Inse

ct b

ite

tria

l (p.

xxx)

Skin

scr

apin

g (p

.26)

Tric

hogr

am(p

.36)

Fung

al c

ultu

re(p

.32)

Biop

sy(p

.38)

Urin

e an

d bl

ood

test

sas

indi

cate

d

Brok

en e

nds

Ana

gen

bulb

s

If n

ot li

kely

,re

cons

ider

eval

uati

on o

fpr

urit

us

Wor

k-up

as

prur

itic

dog

wit

h no

lesi

ons

Inco

nclu

sive

resu

ltTa

pere

d en

dsTe

loge

n bu

lbs

Abn

orm

alha

ir

No

evid

ence

of

hypo

thyr

oidi

smor

hyp

erad

reno

cort

icis

mEv

iden

ce o

f sy

stem

ic s

igns

Ana

gen

deflu

xion

Hor

mon

al d

isea

se,

telo

gen

efflu

vium

Folli

cula

r dy

spla

sia,

co

lor

dilu

tion

alop

ecia

Ever

ythi

ng

is p

ossi

ble

++

--

Fig

ure

2-3

5Th

e D

og

wit

h N

on

infl

amm

ato

ry N

on

pru

riti

c A

lop

ecia

The Dog with Nodules

Key Questions

✓ How old was this patient when clinical signs were first recognized?(p. 3)

✓ How long has the disease been present and how did it progress? (p. 3)

✓ Are there any other animals in the household? (p. 8)

✓ Does anybody in the household have skin disease? (p. 8)

✓ Was the disease treated before? If so, which drugs were used andhow successful was treatment? (p. 8)

Differential Diagnoses The differential diagnoses are predicted primarily based on two sep-arate features: (1) Is there only one lesion (which increases the like-lyhood of neoplasia or a kerion) or are there multiple lesions (whichmay be due to sterile inflammatory diseases, more aggressive neo-plastic disease or severe infection); and (2) Are draining tractsabsent or present (increasing the likelihood of foreign bodies, severebacterial or fungal infection, or sterile inflammatory disease)?

The approach to the dog with nodules is straightforward. Historyand clinical examination are followed by microscopical evalua-tion of impression smears (if draining tracts are present) andaspirates in any dog with nodules (p. 21). In some patients,cytology will reveal an infectious organism or classic neoplasticcells and thus a diagnosis. In most patients, cytologic examina-tion will further narrow the list of differential diagnoses, but abiopsy (p. 38) will be necessary to reach a diagnosis. With nodu-lar lesions, complete excision of one or more nodules should beperformed. If draining tracts are present and/or cytology indi-cates possible infection, a culture may be useful as well. Deeptissue should be submitted rather than a culture swab (p. 28).

76

Tab

le 2

-6D

iffe

ren

tial

Dia

gn

ose

s, C

om

mo

nly

Aff

ecte

d S

ites

, R

eco

mm

end

ed D

iag

no

stic

Tes

ts,

Trea

tmen

t O

pti

on

s, a

nd

Pro

gn

osi

s in

a D

og

wit

h N

od

ule

s

DIS

EA

SE

CO

MM

ON

LYA

FFEC

TED

SIT

ES

DIA

GN

OSTIC

TESTS

TR

EA

TM

EN

TP

RO

GN

OSIS

Abs

cess

es(c

ause

d by

bit

e w

ound

s or

fore

ign

bodi

es)

Cyt

olog

y (p

. 21)

Surg

ical

dra

inag

e, a

ntib

ac-

teri

al t

reat

men

t (p

. 118

)G

ood

Surg

ical

exc

isio

n an

d/or

tum

er s

peci

fic t

hera

py

Surg

ical

exc

isio

n fo

r sol

itar

yle

sion

s; vi

tam

in E

or

syst

emic

glu

coco

rtic

oids

for

syst

emic

dis

ease

Wid

e su

rgic

al e

xcisi

on

follo

wed

by

com

bina

tion

antim

icro

bial

ther

apy

(p. 1

31).

Fair

wit

h ap

prop

riat

em

anag

emen

t

Fair

to

guar

ded

Dox

ycyc

line/

Nia

cina

mid

e(p

. 121

), im

mun

osup

pres

-si

ve t

hera

py (

p. 1

41)

Fair

wit

h ap

prop

riat

em

anag

emen

t

Poor

to

exce

llent

depe

ndin

g on

the

indi

vidu

al t

umor

Neo

plas

ia*

Ster

ile g

ranu

lom

atou

san

d py

ogra

nulo

mat

ous

dise

ase*

(unk

now

n pa

thog

enes

is)

Ster

ile p

anni

culit

is*

(mos

tly

unkn

own

path

o-ge

nesi

s, o

ccas

iona

lly d

ueto

lupu

s er

ythe

mat

osus

)

Opp

ortu

nist

ic m

ycob

ac-

teria

l inf

ectio

n*(u

biqu

itous

, fac

ulta

tivel

ypa

thog

enic

org

anism

s, e.

g.,

Myc

obac

teria

fortu

itum

, M

. che

lone

i, M

. sm

egm

atis

caus

e le

sions

afte

r tra

um-

atic

impl

anta

tion

into

sub-

cuta

neou

s tiss

ue)

Bio

psy

(p. 3

8)

Bio

psy

(p. 3

8), c

ultu

re

(p. 3

2)

Fluc

tuat

ing

nodu

les

mos

tco

mm

only

aro

und

neck

,sh

ould

ers

and

tailb

ase

Var

ies

wit

h in

divi

dual

neo

-pl

asti

c di

seas

es (

Figu

res

2-36

and

2-37

)

Firm

, pai

nles

s, no

npru

riti

cde

rmal

pap

ules

, pla

ques

and

nodu

les

typi

cally

of h

ead,

pinn

ae a

nd d

ista

l lim

bs(F

igur

e 2-

38)

Solit

ary

lesi

on o

ver

ches

t,ne

ck o

r ab

dom

en, m

ulti

ple

trun

kal l

esio

ns w

ith

conc

ur-

rent

ano

rexi

a, le

thar

gy, p

yrex

-ia

(Fi

gure

2-3

9)

Non

heal

ing

ulce

rate

d no

dule

sw

ith

drai

ning

tra

cts.

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8), c

ultu

re (

p. 2

8, 3

2)

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8)

77

Tab

le 2

-6 c

on

tin

ued

DIS

EA

SE

CO

MM

ON

LYA

FFEC

TED

SIT

ES

DIA

GN

OSTIC

TESTS

TR

EA

TM

EN

TP

RO

GN

OSIS

Der

mat

ophy

te k

erio

n(c

ause

d by

der

mat

ophy

tes

and

seco

ndar

y ba

cter

ial

infe

ctio

n)

Cyt

olog

y (p

. 21)

, bio

psy

(p.

38),

fung

al c

ultu

re (

p. 3

2).

Ant

imyc

otic

and

con

cur-

rent

ant

ibac

teri

al t

hera

py(p

. 118

)

Goo

d

Ant

imyc

otic

the

rapy

wit

ham

phot

eric

in B

pos

sibl

y in

com

bina

tion

wit

h ke

to-

cona

zole

or

itra

cona

zole

(p

. 131

)

Ant

imyc

otic

the

rapy

wit

hio

dide

s or

azo

les

(p. 1

31)

Fair

Com

plet

e su

rgic

al e

xcis

ion,

post

surg

ical

ant

ibac

teri

altr

eatm

ent

(p. 1

18)

Fair

wit

h co

mpl

ete

exci

sion

, gua

rded

, if

this

is n

ot p

ossi

ble

Fair

Cry

ptoc

occo

sis*

(Rar

e in

fect

ion

in o

ften

imm

unoc

ompr

omize

d ho

stw

ith u

biqu

itous

, sap

ro-

phyt

ic, y

east

-like

fung

usC

rypt

ococ

cus n

eofo

rman

s)

Bac

teria

l pse

udom

ycet

oma

(non

bran

chin

g ba

cter

ia,

such

as c

oagu

lase

-pos

itive

Stap

hylo

cocc

i im

plan

ted

durin

g tr

aum

a, fo

rm g

rain

sof

com

pact

col

onie

s sur

-ro

unde

d by

pyo

gran

ulom

a-to

us in

flam

mat

ion)

Spor

otri

chos

is*

(cau

sed

by u

biqu

itou

sdi

mor

phic

fung

al s

apro

-ph

yte

Spor

othr

ix s

chen

kii

that

infe

cts

wou

nds)

Zoon

osis

, alt

houg

hzo

onot

ic p

oten

tial

of

cani

ne s

poro

tric

hosi

s is

muc

h lo

wer

tha

n th

at o

ffe

line

spor

otri

chos

is

Bio

psy

(p. 3

8), f

unga

l cul

-tu

re (

p. 3

2)

Nod

ular

furu

ncul

osis

wit

hdr

aini

ng t

ract

s (F

igur

e 2-

40)

Upp

er r

espi

rato

ry, c

utan

eous

,ce

ntra

l ner

vous

and

ocu

lar

sign

s. Pa

pule

s, no

dule

s, ul

cers

and

drai

ning

tra

cts.

Nos

e,lip

s, an

d cl

aw b

eds

may

beaf

fect

ed.

Firm

nod

ules

wit

h dr

aini

ngfis

tula

e

Mul

tipl

e no

dule

s or

ulc

erat

edpl

aque

s on

the

hea

d, p

inna

e,an

d tr

unk.

Cyt

olog

y (p

. 21)

, bio

psy

(p.

38),

bac

teri

al c

ultu

re (

p. 4

3)

Cyt

olog

y (p

. 21)

, bio

psy

(p.

38),

fung

al c

ultu

re (

p. 3

2),

sero

logi

c te

stin

g

78

Eum

ycot

ic m

ycet

oma

(ubi

quit

ous

soil

sapr

o-ph

ytes

cau

se d

isea

seth

roug

h w

ound

con

tam

i-na

tion

)

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8), c

ultu

re (

p. 3

2)W

ide

surg

ical

exc

isio

n fo

l-lo

wed

by

anti

myc

otic

the

ra-

py (

p. 1

31)

base

d on

invi

tro

susc

epti

bilit

y te

stin

g.

Fair

to

guar

ded

depe

ndin

g on

sur

gica

lex

cisi

on.

Wid

e su

rgic

al e

xcis

ion

fol-

low

ed b

y an

tim

ycot

ic t

hera

-py

(p.

131

) ba

sed

on in

vitr

o su

scep

tibi

lity

test

ing

Surg

ical

exc

isio

n or

drai

nage

and

long

-ter

man

tiba

cter

ial t

hera

py(p

. 118

)

Ant

imyc

otic

the

rapy

(p

. 131

)

Ant

imyc

otic

the

rapy

(p. 1

31)

Gua

rded

Gua

rded

to

poor

, if

cent

ral n

ervo

us s

ys-

tem

(C

NS)

invo

lved

and

poor

for

visi

on, i

fuv

eiti

s is

pre

sent

.

Gua

rded

(re

port

edov

eral

l rec

over

y ra

te60

%)

to p

oor

(wit

hbo

ne in

volv

emen

t)

Surg

ical

exc

isio

n fo

llow

edby

long

ter

m a

ntib

acte

rial

ther

apy

(p. 1

18)

Gua

rded

Gua

rded

Phae

ohyp

hom

ycos

is*(w

ound

con

tam

inat

ion

by u

biqu

itous

sapr

ophy

ticfu

ngi w

ith p

igm

ente

dhy

phae

)

Act

inom

ycos

is*

(tra

umat

ic im

plan

tati

onof

or

wou

nd c

onta

min

-at

ion

wit

h fil

amen

tous

,an

aero

bic

Act

inom

yces

spp.

, com

men

sals

of t

heor

al c

avit

y an

d bo

wel

)

Act

inob

acill

osis

*(o

ral c

omm

ensa

l aer

obic

Act

inob

acill

us li

gner

iesii

istr

aum

atic

ally

impl

ante

d,of

ten

thro

ugh

bite

wou

nds)

Bla

stom

ycos

is*(r

are

infe

ctio

n by

the

dim

orph

ic sa

prop

hytic

fung

us B

lasto

myc

es -

derm

atiti

des)

Pos

sible

zoon

osis

(thr

ough

wou

ndco

ntam

inat

ion)

Coc

cidi

oido

myc

osis*

(rar

e in

fect

ion

with

dim

or-

phic

, sap

roph

ytic

fung

usC

occid

ioid

es im

miti

s)

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8), c

ultu

re (

p. 3

2)

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8), f

unga

l cul

ture

(p

. 32)

Bio

psy

(p. 3

8), f

unga

l cul

-tu

re (

p. 3

2).

Nod

ules

wit

h dr

aini

ng t

ract

san

d sc

ar t

issu

e. G

rain

s va

ryin

siz

e, s

hape

, and

col

or.

Oft

en s

olit

ary

subc

utan

eous

nodu

les

on e

xtre

mit

ies.

Subc

utan

eous

sw

ellin

gs, p

os-

sibl

y w

ith

drai

ning

tra

cts

and

yello

w s

ulfu

r gr

anul

es

Thi

ck-w

alle

d ab

sces

ses

of t

hehe

ad, m

outh

, and

lim

bs t

hat

disc

harg

e th

ick

pus

wit

h so

ft,

yello

w g

ranu

les.

Papu

les,

nodu

les,

subc

uta-

neou

s ab

sces

ses

wit

h dr

aini

ngtr

acts

on

face

and

feet

.C

oncu

rren

t an

orex

ia, w

eigh

tlo

ss, c

ough

ing,

dys

pnea

, ocu

-la

r di

seas

e

Papu

les,

nodu

les,

absc

esse

s,an

d dr

aini

ng t

ract

s ov

erin

fect

ed b

ones

. Con

curr

ent

anor

exia

, wei

ght

loss

, cou

gh-

ing,

dys

pnea

, ocu

lar

dise

ase,

CN

S si

gns

poss

ible

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8), c

ultu

re (

p. 3

2)

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8), c

ultu

re (

p. 3

2)

79

Tab

le 2

-6 c

on

tin

ued

DIS

EA

SE

CO

MM

ON

LYA

FFEC

TED

SIT

ES

DIA

GN

OSTIC

TESTS

TR

EA

TM

EN

TP

RO

GN

OSIS

His

topl

asm

osis

*(u

ncom

mon

infe

ctio

nw

ith

dim

orph

ic, s

apro

-ph

ytic

soi

l fun

gus

Hist

opla

sma

caps

ulat

um)

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8), f

unga

l cul

ture

(p

. 32)

Ant

imyc

otic

age

nts

(p. 1

31)

Fair

to

good

for

dogs

wit

h pu

lmon

ary

dise

ase,

gua

rded

to

grav

e fo

r di

ssem

in-

ated

dis

ease

Surg

ical

dra

inag

e an

d an

ti-

bact

eria

l the

rapy

(p.

118

)ba

sed

on in

vit

ro s

usce

pti-

bilit

y te

stin

g

Com

bina

tion

ant

imic

robi

alth

erap

y (p

. 131

), fr

eque

nteu

than

asia

due

to

publ

iche

alth

con

cern

s

Poor

Wid

e su

rgic

al e

xcis

ion

Gua

rded

to

poor

Gua

rded

Noc

ardi

osis*

(Noc

ardi

asp

p. a

re so

ilsa

prop

hyte

s and

cau

se re

s-pi

rato

ry, c

utan

eous

, or d

is-se

min

ated

infe

ctio

ns)

Pyth

iosi

s*(i

nfec

tion

wit

h aq

uati

cfu

ngi b

y ex

posu

re o

f dam

-ag

ed s

kin

to in

fect

ed s

tag-

nant

wat

er)

Tube

rcul

osis

*(r

are

infe

ctio

n in

sm

all

anim

als

caus

ed b

yM

ycob

acte

rium

tube

rcul

o-sis

, bo

vis

and

rare

lyav

ium

, pre

dom

inan

tly

resp

irat

ory

and

dige

stiv

ele

sion

s)

Rad

iogr

aphs

, bio

psy

(p. 3

8),

cultu

re (

p. 3

2)

Papu

les,

nodu

les,

ulce

rs, a

nddr

aini

ng tr

acts

. Con

curr

ent

anor

exia

, wei

ght l

oss a

ndfe

ver,

coug

hing

, dys

pnea

, gas

-tr

oint

estin

al a

nd o

cula

r dise

ase

Ulc

erat

ed n

odul

es a

ndab

sces

ses,

ofte

n w

ith

drai

ning

trac

ts, o

n th

e lim

bs a

nd fe

et

Ulc

erat

ed n

odul

es o

f the

face

and

legs

dev

elop

into

bog

gym

asse

s w

ith

ulce

rati

on a

nddr

aini

ng t

ract

s

Ulc

ers,

plaq

ues,

and

nodu

les

on h

ead,

nec

k, a

nd li

mbs

tha

tdi

scha

rge

yello

w-g

reen

pus

wit

h un

plea

sant

sm

ell

Bio

psy

(p. 3

8), c

ultu

re

(p. 3

2)

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8), c

ultu

re (

p. 3

2)

80

81

Figu

re 2

-36

His

tioc

ytom

a in

a

2-ye

ar-o

ld c

astr

ated

Jack

Rus

sell

mix

edbr

eed.

Figu

re 2

-38

Nod

ules

an

d ul

cers

in

a 2-

year

-old

spa

yed

Mal

tese

wit

h s

teri

legr

anul

omat

ous

dise

ase.

Figu

re 2

-37

Seb

aceo

us c

ysts

in a

cas

-tr

ated

Box

er,.

(Cou

rtes

yof

Dr.

Son

ya B

ette

nay

.)

Figu

re 2

-39

Ste

rile

pan

nic

ulit

is w

ith

ulce

rs a

nd

nod

ules

in a

9-ye

ar-o

ld c

astr

ated

En

glis

h S

prin

ger

Spa

nie

l.

82

Figure 2-41The Dog with Nodules

Figure 2-40Dermatophyte kerion.(Courtesy of Dr. Sonya Bettenay.)

Bacterial infection

Cytology

Antibacterial treatment(p.118)

Biopsy (p. 38), culture (p. 32)

Biopsy (p. 38), culture (p. 32)(48 hours post antibacterial

treatment)

No resolution Resolution

(p. 21)

No microorganisms,otherwise inconclusive

Diagnostic result Neutrophils and cocci,otherwise inconclusive

83

The Dog with Nasal DermatitisKey Questions

✓ How old was this patient when clinical signs were first recognized?(p. 3)

✓ How long has the disease been present and how did it progress?(p. 3)

✓ Is the disease seasonal? (p. 6)

✓ Are there any other animals in the household? (p. 8)

✓ Does anybody in the household have skin disease? (p. 8)

✓ Was the disease treated before? If so, which drugs were used andhow successful was treatment? (p. 8)

✓ When was the last medication given? (p. 9)

Differential DiagnosesDifferential diagnoses are listed in Table 2-7. If lesions are present onthe haired dorsal muzzle and the planum nasale, it is important tofind out whether the first changes occurred on the planum nasale(possibly just as depigmentation) or in the haired skin. First changesin the haired skin indicate follicular diseases such as bacterial folli-culitis, demodicosis, and dermatophytosis are more likely. If theplanum nasale is affected first, immune-mediated skin diseases such asdiscoid lupus erythematosus or pemphigus foliaceus are higher on thelist of possible conditions to be ruled out. If initial in-house tests suchas skin scrapings (p. 26) and cytology (p. 21) are negative or nondiag-nostic, biopsy (p. 38) is the next step.

84

Tab

le 2

-7D

iffe

ren

tial

Dia

gn

ose

s, C

om

mo

nly

Aff

ecte

d S

ites

, R

eco

mm

end

ed D

iag

no

stic

Tes

ts,

Trea

tmen

t O

pti

on

s, a

nd

Pro

gn

osi

s in

a D

og

wit

h N

asal

Der

mat

itis

DIS

EA

SE

AFF

EC

TED

SIT

ES

DIA

GN

OSTIC

TESTS

TR

EA

TM

EN

TP

RO

GN

OSIS

Dis

coid

lupu

s er

ythe

m-

atos

us*

(Im

mun

e-m

edia

t-ed

rea

ctio

n ag

ains

t ba

sal

cell

laye

r m

ay b

e ag

grav

at-

ed b

y U

V-l

ight

exp

osur

e)

Bio

psy

(p. 3

8)Su

n av

oida

nce,

wat

er-p

roof

sun

scre

ens,

vit

amin

E(2

00-4

00 m

g q

12 h

r),

doxy

cycl

ine

and

niac

i-na

mid

e (p

. 121

), im

mun

o-su

ppre

ssiv

e th

erap

y (p

. 141

)

Fair

Imm

unos

uppr

essi

ve t

hera

py(p

. 141

)

Loca

lized

form

: 95%

res

olve

spon

tane

ousl

y, t

hus

beni

gnne

glec

t or

ant

imic

robi

altr

eatm

ent

only

(p.

118

).G

ener

aliz

ed fo

rm: A

mit

raz,

iver

mec

tin,

milb

emyc

in

(p. 1

33),

ant

ibac

teri

al t

reat

-m

ent

for

seco

ndar

y in

fec-

tion

(p.

118

)

Fair

Ant

ibac

teri

al t

reat

men

t (p

. 118

)G

ood,

if u

nder

lyin

gdi

seas

e ca

n be

iden

ti-

fied

and

trea

ted

appr

o-pr

iate

ly. R

elap

se li

kely

,if

this

is n

ot p

ossi

ble

Fair

Pem

phig

us fo

liace

us(I

mm

une

med

iate

d re

ac-

tion

agai

nst d

ismon

orm

alpr

otei

ns)

Bac

teria

l inf

ectio

n (t

ypi-

cally

by

Stap

hylo

cocc

usin

term

ediu

sand

typi

cally

seco

ndar

y to

an

unde

rly-

ing

dise

ase)

Dem

odic

osis

(pr

obab

ly a

here

dita

ry sp

ecifi

c T-

cell

defe

ct th

at p

erm

its a

bnor

-m

al p

rolif

erat

ion

ofD

emod

ex c

anis,

a n

orm

alco

mm

ensa

l mite

of c

anin

esk

in. T

his p

rolif

erat

ion

lead

s to

a fu

rthe

r par

asite

-in

duce

d im

mun

osup

pres

-sio

n. A

dult-

onse

t dem

odi-

cosis

freq

uent

ly se

cond

ary

to h

orm

onal

dise

ases

, neo

-pl

asia

, ste

roid

s, or

oth

erch

emot

hera

py.)

Dee

p sk

in s

crap

ings

(p.

28)

,ha

ir p

luck

s (p

. 36)

, bio

psy

(p. 3

8), e

limin

atio

n di

et

(p. 4

6)

Plan

um n

asal

e, p

erio

cula

rar

ea, l

ips,

dors

al m

uzzl

e, p

in-

nae

(Fig

ure

2-42

)

Plan

um n

asal

e, p

erio

cula

r are

a,lip

s, do

rsal

muz

zle, i

nner

surfa

ceof

pin

nae,

foot

pad

s, gr

oin,

cla

wfo

lds,

nipp

les (

in c

ats)

(Fi

gure

s2-

21, 2

-22,

2-2

3, a

nd 2

-43)

Dep

igm

enta

tion

of p

lanu

mna

sale

in G

erm

an S

heph

erd

Dog

s w

ith a

topy

(Fi

gure

2-4

4)

Loca

lized

form

: Foc

al e

ryth

ema,

alop

ecia

and

scal

ing,

mos

t com

-m

only

on

the

face

(<

4 sit

es).

Gen

eral

ized

form

: Ery

them

a,al

opec

ia, p

apul

es, p

laqu

es, p

us-

tule

s and

cru

sts w

here

larg

ear

eas,

mor

e th

an 5

are

as, o

rpa

ws a

re in

volv

ed (

Figu

res

2-15

, 2-1

6, a

nd 2

-17)

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8)

Bio

psy

(p. 3

8)

85

Der

mat

ophy

tosi

s (d

er-

mat

ophy

tes

are

tran

smit

-te

d by

con

tact

wit

h fu

n-ga

l ele

men

ts)

Woo

d’s l

amp

(p. 3

0), t

ri-ch

ogra

m (

p. 3

6), f

unga

l cul

-tu

re (

p. 3

2), b

iops

y (p

. 38)

Ant

imyc

otic

age

nts

such

as

gris

eofu

lvin

or

keto

cona

zole

(p. 1

31).

Top

ical

ant

ifung

alsh

ampo

os m

ay d

ecre

ase

cont

amin

atio

n of

env

iron

-m

ent.

Goo

dFa

ce, p

inna

e, p

aws

(Fig

ure

2-18

)

Ant

imyc

otic

the

rapy

wit

ham

phot

eric

in B

pos

sibl

y in

com

bina

tion

wit

h ke

to-

cona

zole

or

itra

cona

zole

(p

. 131

)

Fair

Cry

ptoc

occo

sis*

(Rar

e in

fect

ion

in o

ften

imm

unoc

ompr

omize

dho

st w

ith u

biqu

itous

,sa

prop

hytic

, yea

st-li

kefu

ngus

Cry

ptoc

occu

s neo

-fo

rman

s)

Upp

er r

espi

rato

ry, c

utan

eous

,ce

ntra

l ner

vous

and

ocu

lar

sign

s. Pa

pule

s, no

dule

s, ul

cers

and

drai

ning

tra

cts.

Nos

e,lip

s, an

d cl

aw b

eds

may

beaf

fect

ed.

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8), f

unga

l cul

ture

(p

. 32)

, ser

olog

ic t

esti

ng

Ant

imyc

otic

the

rapy

wit

hio

dide

s or

azo

les

(p. 1

31)

Fair

Spor

otri

chos

is*

(cau

sed

by u

biqu

itou

sdi

mor

phic

fung

al s

apro

-ph

yte

Spor

othr

ix s

chen

kii

that

infe

ct w

ound

s)Zo

onos

is, a

ltho

ugh

zoon

otic

pot

enti

al o

fca

nine

spo

rotr

icho

sis

ism

uch

low

er t

han

that

of

felin

e sp

orot

rich

osis

Bio

psy

(p. 3

8), f

unga

l cul

-tu

re (

p. 3

2)M

ulti

ple

nodu

les

or u

lcer

ated

plaq

ues

on t

he h

ead,

pin

nae,

and

trun

k.

Figu

re 2

-42

Dep

igm

enta

tion

, ero

sion

s,an

d ul

cers

in a

3-y

ear-

old

spay

ed A

ustr

alia

n Sh

ephe

rdm

ixed

bre

ed w

ith

disc

oid

lupu

s er

ythe

mat

osus

.

86

Figu

re 2

-44

Bac

teri

al f

acia

l an

dn

asal

pyo

derm

a in

a

5-ye

ar-o

ld c

astr

ated

Bul

l T

erri

er.

Not

e th

atth

e pl

anum

nas

ale

issp

ared

. (C

ourt

esy

ofD

r. S

onya

Bet

ten

ay.)

Figu

re 2

-43

Pem

phig

us fo

liace

usw

ith

dep

igm

enta

tion

,er

osio

ns,

an

d cr

usti

ng

in a

7-y

ear-

old

mal

eG

olde

n R

etri

ever

.

Fig

ure

2-4

5Th

e D

og

wit

h N

asal

Der

mat

itis

Bact

eria

l inf

ecti

on

Biop

sy (

p. 3

8)

Cyt

olog

y (p

. 21)

, ski

n sc

rapi

ngs

(p. 2

6), f

unga

l cul

ture

(p.

32)

Ant

imic

robi

al t

reat

men

t(p

. 118

)

Ant

ipar

asit

ic t

reat

men

t(p

. 133

)

Ant

ifun

gal t

reat

men

t(p

. 130

)

Cyt

olog

yA

ll te

sts

nega

tive

Skin

scr

apin

gFu

ngal

cul

ture

-+

++

87

The Cat with Miliary Dermatitis

Key Questions

✓ How old was this patient when clinical signs were first recognized?(p. 3)

✓ How long has the disease been present and how did it progress? (p. 3)

✓ On which part of the body did the problem start? (p. 4)

✓ Is the disease seasonal? (p. 6)

✓ Are there other clinical signs such as sneezing, coughing, or diarrhea? (p. 7)

✓ What do you feed the animal? Was a special diet used in the past?(p. 7)

✓ Are there any other animals in the household? (p. 8)

✓ Does anybody in the household have skin disease? (p. 8)

✓ Was the disease treated before? If so, which drugs were used andhow successful was treatment? (p. 8)

✓ What is used for flea control now? (p. 9)

✓ When was the last medication given? (p. 9)

Differential Diagnoses Classic lesions of miliary dermatitis are focal or generalized smallpapules and crusts (Figures 2-46 and 2-47). Miliary dermatitis isnot a diagnosis but rather a descriptive term for a feline cutaneousreaction pattern with many possible causes. Most cats suffer froman underlying flea-bite hypersensitivity. The differential diagnosesfor feline miliary dermatitis are listed in Table 2-8.

88

Tab

le 2

-8D

iffe

ren

tial

Dia

gn

ose

s, C

om

mo

nly

Aff

ecte

d S

ites

, R

eco

mm

end

ed D

iag

no

stic

Tes

ts,

Trea

tmen

t O

pti

on

s, a

nd

Pro

gn

osi

s in

a C

at w

ith

Mili

ary

Der

mat

itis

DIS

EA

SE

CO

MM

ON

LYA

FFEC

TED

SIT

ES

DIA

GN

OSTIC

TESTS

TR

EA

TM

EN

TP

RO

GN

OSIS

Flea

-bit

e hy

pers

ensi

tivi

tyFl

ea c

ontr

ol t

rial

(p.

48)

Flea

con

trol

(p.

136

), g

luco

-co

rtic

oids

(p.

129

), a

ntih

ista-

min

es (

p. 1

25),

ess

entia

l fat

tyac

ids (

p. 1

28).

Goo

d fo

r w

ell-

bein

g of

the

pati

ent

wit

h co

n-ti

nued

man

agem

ent;

guar

ded

for

cure

Alle

rgen

-spe

cific

imm

unot

her-

apy

(p.1

23),

ant

ihist

amin

es

(p. 1

25),

ess

entia

l fat

ty a

cids

(p. 1

28),

glu

coco

rtic

oids

p.

129

).

Indo

or c

onfin

emen

t (a

tle

ast

duri

ng d

usk

and

daw

n), i

nsec

t re

pelle

nts

such

as

pyre

thri

ne s

pray

s.

Ant

ibac

teri

al a

gent

s (p

. 119

)

Goo

d fo

r w

ell-

bein

gof

the

pat

ient

wit

hco

ntin

ued

man

age-

men

t; g

uard

ed fo

r cu

re

Goo

d, b

ut r

elap

selik

ely

if un

derl

ying

dise

ase

is n

ot id

enti

-fie

d an

d tr

eate

d

Avo

idan

ce, a

ntih

ista

min

es(p

. 125

), e

ssen

tial

fatt

y ac

ids

(p. 1

28),

glu

coco

rtic

oids

(p

. 129

).

Exce

llent

, if o

ffend

ing

prot

ein(

s) is

(ar

e)id

enti

fied

and

avoi

ded.

Onl

y fa

ir w

ith

cont

in-

ued

man

agem

ent,

ifno

t. G

uard

ed fo

r cu

re

Goo

d fo

r w

ell-

bein

gof

the

pat

ient

wit

hco

ntin

ued

man

age-

men

t; g

uard

ed fo

r cu

re

Ato

py*

(hyp

erse

nsiti

vity

to a

ero-

alle

rgen

s suc

h as

pol

lens

,ho

use

dust

mite

s or m

old

spor

es)

Food

adv

erse

rea

ctio

n(m

ay o

r m

ay n

ot b

e al

ler-

gic,

com

mon

ly r

eact

ion

agai

nst

a pr

otei

n, r

arel

y an

addi

tive

, clin

ical

ly in

dis-

ting

uish

able

from

ato

py)

Mos

quito

-bite

hyp

erse

nsi-

tivity

(an

alle

rgic

reac

tion

to sa

livar

y an

tigen

s of

mos

quito

es)

Bac

teria

l sup

erfic

ial f

olli-

culit

is (c

ause

d by

Stap

hylo

cocc

i and

seco

nd-

ary

to o

ther

dise

ases

)

Kee

ping

cat

indo

ors f

orso

me

days

, bio

psy

(p. 3

8)

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8)

Dor

sal l

umbo

sacr

al a

rea,

cau

-da

l hal

f of t

he b

ody

or g

ener

-al

ized

dis

ease

(Fi

gure

s 2-

46an

d 2-

47)

Hea

d an

d ne

ck, g

ener

aliz

eddi

seas

e.

Cra

nial

hal

f of t

he b

ody

orge

nera

lized

dis

ease

Papu

les

and

crus

ts o

n do

rsal

muz

zle,

late

ral a

spec

ts o

f pin

-na

e, a

nd fo

ot p

ads

(Fig

ures

2-

48 a

nd 2

-49)

Hea

d an

d ne

ck o

r ge

nera

lized

Elim

inat

ion

diet

(p.

46)

Dia

gnos

is ba

sed

on h

istor

y,ph

ysic

al e

xam

inat

ion

and

rulin

g ou

t diff

eren

tial d

iag-

nose

s. In

trad

erm

al sk

in te

stal

low

s for

mul

atio

n of

imm

unot

hera

py

89

Oto

dect

es c

ynot

isin

fest

a-tio

n (m

ay c

ause

mor

e th

anju

st o

titis

exte

rna)

Supe

rfic

ial s

kin

scra

ping

s(p

. 26)

, mit

icid

al t

reat

men

ttr

ial (

p. 4

9)

Ant

ipar

asit

ic a

gent

s (p

. 133

)Ex

celle

nt

Imm

unos

uppr

essi

on

(p. 1

41)

Ant

ifung

al a

gent

s (p

. 130

)

Ant

ipar

asit

ic a

gent

s (p

. 133

)

Ant

ipar

asit

ic a

gent

s (p

. 133

)

Gua

rded

for

cur

e in

catt

erie

s an

d Pe

rsia

nca

ts, g

ood

othe

rwis

e.

Exce

llen

t

Exce

llen

t

Glu

coco

rtic

oids

(p

. 129

), c

hem

othe

rapy

Fair

Fair

Pem

phig

us fo

liace

us*

Mas

t ce

ll tu

mor

*

Der

mat

ophy

tosi

s(i

n th

is fo

rm t

ypic

ally

caus

ed b

y M

. ca

nis)

Che

ylet

iello

sis

(Dep

endi

ng o

n lo

cati

ona

rare

to

com

mon

con

ta-

giou

s di

seas

e ca

used

by

Che

ylet

iella

bla

kei)

Felin

e sc

abie

s(a

hig

hly

cont

agio

us d

is-

ease

cau

sed

by N

otoe

dres

cati)

Cyt

olog

y (p

. 21)

, Woo

d’s

lam

p (p

. 30)

, fun

gal c

ultu

re(p

. 32)

, bio

psy

(p. 3

8)

Supe

rfic

ial s

kin

scra

ping

s(p

. 26)

, sar

copt

es t

reat

men

ttr

ial (

p. 4

9), f

lea

com

bing

and

mic

rosc

opic

ally

eva

lu-

atin

g de

bris

cov

ered

wit

hm

iner

al o

il in

a P

etri

dis

h

Supe

rfic

ial s

kin

scra

ping

s(p

. 26)

, sar

copt

es t

reat

-m

ent

tria

l (p.

49)

Oti

tis

exte

rna,

pin

nae,

face

,ne

ck, t

high

s, ta

il, a

nd t

ailb

ase

Yello

wis

h to

bro

wni

sh c

rust

sm

ay b

e m

ista

ken

for

the

typi

-ca

lly s

mal

ler

and

dark

er c

las-

sica

l mili

ary

derm

atit

isle

sion

s. H

ead,

inne

r pi

nnae

,cl

aw b

eds,

nipp

les

Papu

lar

form

may

occ

asio

nal-

ly b

e m

ista

ken

for

mili

ary

derm

atit

is

Foca

l or

gene

raliz

ed

Typi

cally

cha

ract

eriz

ed b

yex

cess

ive

scal

ing

part

icul

arly

on t

he d

orsu

m, b

ut o

ccas

ion-

ally

gen

eral

ized

mili

ary

der-

mat

itis

Pinn

ae, f

ace,

nec

k, g

ener

al-

ized

dis

ease

.

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8)

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8)

90

Figu

re 2

-46

Ero

sion

s an

d cr

uste

dpa

pule

s in

a c

at w

ith

mili

ary

derm

atit

is.

Figu

re 2

-48

Nas

al d

erm

atit

is i

n a

5-ye

ar-o

ld c

astr

ated

DH

S w

ith

mos

quit

o-bi

te h

yper

sen

siti

vity

.

Figu

re 2

-47

Mili

ary

derm

atit

is in

ado

mes

tic

shor

thai

r ca

t(D

SH

).

Figu

re 2

-49

Cru

stin

g on

th

e ed

ges

ofth

e fo

otpa

ds d

ue t

om

osqu

ito-

bite

hyp

erse

n-

siti

vity

in a

5-y

ear-

old

spay

ed D

SH

. (C

ourt

esy

of D

r. S

onya

Bet

ten

ay.)

91

Figure 2-50The Cat with Miliary Dermatitis

Ectoparasite infestation with or without infection

Insect bite hypersensitivity

Insect control trial (p. 48) with or without antimicrobial treatment (p. 118)

Cytology (p. 21), skin scrapings (p. 26)

Antifungal therapy(p. 130)

CytologyScrapings -

- CytologyScrapings

- CytologyScrapings

CytologyScrapings -

++++

No improvement

Elimination diet(p. 46)

Fungal culture(p. 32)

Response

Rechallenge

No response

Depending on patient, owner and finances

Complete resolution

- +

No relapse Chronic dermatitis

DiagnosticRelapse

Relapse

Monitoring

Dermatophytosis

Skin testing

Food adverse reaction

Biopsy(p. 38)

92

The Cat withNoninflammatory AlopeciaKey Questions:

✓ How old was this patient when clinical signs were first recognized? (p. 3)

✓ How long has the disease been present and how did it progress? (p. 3)

✓ On which part of the body did the problem start? (p. 4)

✓ Is the disease seasonal? (p. 6)

✓ Are there other clinical signs such as sneezing, coughing or diarrhea? (p. 7)

✓ What do you feed the animal? Was a special diet used in the past? (p. 7)

✓ Are there any other animals in the household? (p. 8)

✓ Does anybody in the household have skin disease? (p. 8)

✓ Was the disease treated before? If so, which drugs were used and how successful was treatment? (p. 8)

✓ What is used for flea control now? (p. 9)

✓ When was the last medication given? (p. 9)

Differential Diagnoses Noninflammatory alopecia is a feline cutaneous reaction pattern that may have various causes. Hormonal alopecia is extremely rare in the feline and typically affected cats show other severe signs. Psychogenicalopecia in the cat is greatly overdiagnosed. The disease usually affectspure-bred cats with a nervous disposition. Environmental changes such as a new partner, baby, pet, or a move to a new house precede clinicalsigns. Most cats with noninflammatory alopecia are pruritic as a result of allergies and may be closet groomers. Many cats previously diagnosedwith hormonal alopecia and treated successfully with medroxyprogesteronacetate or megestrol acetate have responded because the anti-inflam-matory action of these medications have controlled their prurituscaused by allergies, not because of a correction of their hormonalimbalance. The differential diagnoses for feline noninflammatoryalopecia are listed in Table 2-9.

93

Tab

le 2

-9D

iffe

ren

tial

Dia

gn

ose

s, C

om

mo

nly

Aff

ecte

d S

ites

, R

eco

mm

end

ed D

iag

no

stic

Tes

ts,

Trea

tmen

t O

pti

on

s, a

nd

Pro

gn

osi

s in

a C

at w

ith

No

nin

flam

mat

ory

Alo

pec

ia

DIS

EA

SE

CO

MM

ON

LYA

FFEC

TED

SIT

ES

DIA

GN

OSTIC

TESTS

TR

EA

TM

EN

TP

RO

GN

OSIS

Flea

-bit

e hy

pers

ensi

tivi

tyTr

icho

gram

(p.

36)

, fle

aco

ntro

l tri

al (

p. 4

8)Fl

ea c

ontr

ol (

p. 1

36),

glu

-co

cort

icoi

ds (

p. 1

29),

ant

i-hi

stam

ines

(p.

125

), e

ssen

-ti

al fa

tty

acid

s (p

. 128

)

Goo

d fo

r w

ell-

bein

g of

the

pati

ent

wit

h co

n-ti

nued

man

agem

ent;

guar

ded

for

cure

.

Alle

rgen

-spe

cific

imm

unot

hera

py (

p. 1

23),

antih

istam

ines

(p.

125

),es

sent

ial f

atty

aci

ds (

p. 1

28),

gluc

ocor

ticoi

ds (

p. 1

29)

Ant

ifung

al a

gent

s (p

. 131

)

Envi

ronm

enta

l cha

nges

, glu

-co

cort

icoi

ds (

p. 1

29),

anx

i-ol

ytic

dru

gs.

Poor

for

catt

erie

s an

dPe

rsia

ns, g

ood

othe

r-w

ise.

Fair

Avo

idan

ce, a

ntih

ista

min

es(p

. 125

), e

ssen

tial

fatt

yac

ids

(p. 1

28),

gluc

ocor

tico

ids

(p. 1

29)

Exce

llent

, if o

ffend

ing

prot

ein(

s) is

(ar

e)id

enti

fied

and

avoi

ded.

Fa

ir w

ith

cont

inue

dm

anag

emen

t, if

offe

ndin

g pr

otei

ns a

reno

t id

enti

fied.

Gua

rded

for

cure

.

Goo

d fo

r w

ell-

bein

gof

the

pat

ient

wit

hco

ntin

ued

man

age-

men

t; g

uard

ed fo

rcu

re.

Ato

py*

(hyp

erse

nsiti

vity

to a

ero-

alle

rgen

s suc

h as

pol

lens

,ho

use

dust

mite

s, or

mol

dsp

ores

)

Food

adv

erse

reac

tion

(may

or m

ay n

ot b

e al

ler-

gic,

com

mon

ly re

acti

on to

a pr

otei

n, ra

rely

an

addi

-ti

ve, c

linic

ally

indi

stin

-gu

isha

ble

from

ato

py)

Der

mat

ophy

tosi

s(i

n th

is fo

rm t

ypic

ally

caus

ed b

y M

. ca

nis)

Psyc

hoge

nic

alop

ecia

(due

to e

xces

sive

groo

m-

ing

caus

ed b

y ps

ycho

logi

-ca

l fac

tors

)

Tric

hogr

am (

p. 3

6), c

ytol

ogy

(p. 2

1), W

ood’

s lam

p (p

.30

), fu

ngal

cul

ture

(p.

32)

,bi

opsy

(p.

38)

Hist

ory

(p. 2

), tr

icho

gram

(p. 3

6)

Dor

sal l

umbo

sacr

al a

rea,

cau

-da

l hal

f of t

he b

ody

or g

ener

-al

ized

dis

ease

Cra

nial

hal

f of t

he b

ody,

ven

-tr

um, f

lank

s or

gen

eral

ized

dise

ase

(Fig

ure

2-51

)

Cra

nial

hal

f of t

he b

ody,

ven

-tr

al a

bdom

en o

r ge

nera

lized

dise

ase

Foca

l or

gene

raliz

ed

Med

ial f

orel

egs,

caud

alab

dom

en, i

ngui

nal r

egio

n.

Tric

hogr

am (

p. 3

6), e

limin

a-tio

n di

et (

p. 4

6)

Dia

gnos

is ba

sed

on h

istor

y,ph

ysic

al e

xam

inat

ion,

tri-

chog

ram

(p.

36)

and

rulin

gou

t diff

eren

tial d

iagn

oses

.In

trad

erm

al sk

in te

st a

llow

sfo

rmul

atio

n of

imm

unot

her-

apy

94

Tab

le 2

-9 c

on

tin

ued

DIS

EA

SE

CO

MM

ON

LYA

FFEC

TED

SIT

ES

DIA

GN

OSTIC

TESTS

TR

EA

TM

EN

TP

RO

GN

OSIS

Hyp

erad

reno

cort

icis

m*

(ver

y ra

re, s

imila

r pa

tho-

gene

sis

to s

ame

cond

itio

nin

dog

s)

Ult

raso

nogr

aphy

, AC

TH

stim

ulat

ion

test

, low

-dos

ede

xam

etha

sone

sup

pres

-si

on t

est

Met

yrap

one,

o,p

´-D

DD

,ke

toco

nazo

le h

ave

been

used

Poor

Add

ress

ing

the

unde

rlyi

ngca

use

Not

nee

ded,

if s

tres

s w

as a

sing

ular

eve

nt

Exce

llent

Exce

llent

if c

ausa

tive

fact

or is

rem

oved

Ana

gen

deflu

xion

(sev

ere

dise

ases

or a

ntim

i-to

tic d

rugs

inte

rfere

with

hair

grow

th, r

esul

ting

inab

norm

al h

air s

hafts

,w

hich

cau

ses h

air t

o br

eak

off s

udde

nly)

Telo

gen

efflu

vium

(sev

ere

stre

ss, s

uch

assh

ock,

feve

r, su

rger

y ca

us-

es a

brup

t ce

ssat

ion

of h

air

grow

th a

nd s

wit

chin

g to

cata

gen

and

then

tel

ogen

phas

es in

man

y fo

llicl

es,

whi

ch a

re a

ll sh

ed s

imul

-ta

neou

sly

1 to

3 m

onth

saf

ter

the

insu

lt)

Poly

dips

ia, p

olyu

ria,

wei

ght

loss

, ano

rexi

a, p

olyp

hagi

a,de

pres

sion

, mus

cle

was

ting

,al

opec

ia (

flank

s, ve

ntru

m, o

ren

tire

tru

nk),

frag

ile s

kin

Alo

peci

a of

sud

den

onse

t

Foca

l to

gene

raliz

ed a

lope

cia

His

tory

, tri

chog

ram

(p.

36)

His

tory

, tri

chog

ram

(p

. 36)

Figu

re 2

-51

Non

infl

amm

ator

y al

opec

ia i

n a

cat

wit

h a

topy

.(C

ourt

esy

of D

r. W

ayn

e R

osen

kran

tz.)

95

Figure 2-52 The Cat with Noninflammatory Alopecia

Trichogram (p.36)

Symptomatictreatment (p.123)

Broken offhair shafts

Fungalspores

History

History

Biopsy

Taperedhair shafts

- +

No response

No relapse

Monitoring

Relapse lateron

Relapse

Dermatophytosis

Atopy

Blood tests

Remission No response

Insect bite hypersensitivity

Telogeneffluvium

Food adversereaction

Elimination diet (p.46)

Remission

Rechallenge

Skin testing

+-Psychogenicalopecia

Fungalculture (p. 32)

Insect controltrial (p. 48)

96

The Cat with Lesions of the EosinophilicGranuloma Complex

Key Questions

✓ How old was this patient when clinical signs were first recognized?(p. 3)

✓ Is the disease seasonal? (p. 6)

✓ Are there other clinical signs such as sneezing, coughing, or diar-rhea? (p. 7)

✓ What do you feed the animal? Was a special diet used in the past?(p. 7)

✓ Was the disease treated before? If so, which drugs were used andhow successful was treatment? (p. 8)

✓ What is used for flea control now? (p. 9)

✓ When was the last medication given? (p. 9)

Differential Diagnoses All subsets of the eosinophilic granuloma are mucocutaneousreaction patterns in the cat.

✓ Indolent (or eosinophilic or rodent) ulcer commonly affectsthe upper lip unilaterally or bilaterally (Figure 2-53), but mayoccur in the oral cavity or elsewhere on the body (Figure 2-54).The well-circumscribed ulcers with raised borders are rarelypainful or pruritic; frequently the owner is more bothered by thelesions than the cat. The differential diagnoses of the felineeosinophilic ulcer are neoplastic diseases such as squamous cellcarcinoma and infectious ulcers (eosinophilic ulcers are oftensecondarily infected as well). Diagnosis is confirmed by biopsy(p. 38). Prior antimicrobial treatment (p. 118) is recommendedif cytology (p. 21) is indicative of infection.

97

✓ Eosinophilic plaques occur typically on the abdomen or medialthighs, are well-circumscribed, and severely pruritic (Figure 2-55).

✓ Eosinophilic (linear) granulomas are nonpruritic, raised, firm,yellowish, and clearly linear plaques and occur most commonlyon the caudal thighs (Figure 2-56).

Differential diagnoses of both eosinophilic plaques and granulo-mas include neoplasias and bacterial and fungal granulomas(Table 2-10). Diagnostic procedures of choice are cytology (p. 21)and biopsy (p. 38). After the diagnosis has been confirmed, theunderlying cause needs to be identified, if possible, and treated.

Figure 2-53Indolent ulcer in a 2-year-old femaleDSH.

Figure 2-54Indolent ulcer of the nipple in a 4-year-old female DSH.

Figure 2-55Eosinophilic plaques in the inguinal area of a DSH. (Courtesy of Dr. SonyaBettenay.)

98

Figure 2-56Linear granuloma in a male 8-year-oldDSH.

Table 2-10Underlying Causes and Recommended Diagnostic Tests

in a Cat with Lesions of the Eosinophilic Granuloma Complex

DISEASE DIAGNOSTIC TESTS TREATMENT

Flea-bite hypersensitivity Flea control (p. 136), glucocorticoids (p. 129), antihistamines (p. 125), essential fattyacids (p. 128)

Atopy(hypersensitivity to aero-allergens such as pollens,house dust mites, or moldspores)

Food adverse reaction(may or may not be aller-gic, commonly reaction toa protein, rarely an addi-tive, clinically indistin-guishable from atopy)

Idiopathic eosinophilicgranuloma (most likelygenetic basis)

Glucocorticoids (p. 129),antibiotics (p. 119)

Flea control trial (p. 136)

Diagnosis based on history,physical examination and ruling out differential diag-noses. Intradermal skin testallows formulation ofimmunotherapy.

Elimination diet (p. 46)

Ruling out possible hypersen-sitivities

Avoidance, antihistamines(p. 125), essential fattyacids (p. 128),glucocorticoids (p. 129)

Allergen-specificimmunotherapy (p. 123),antihistamines (p. 125),essential fatty acids (p.128),glucocorticoids (p. 129)

99

Figure 2-57 The Cat with Lesions of the Eosinophilic

Granuloma Complex

Insect bite hypersensitivity

Cytology(p. 21)

- +

Adverse foodreaction

Remission No improvement

No change Remission

No relapse Relapse

Insect control (p. 48) with or without antimicrobial treatment (p.118)

Elimination diet(p. 46)

Rechallenge

Skin testing MonitoringRelapselater on

-+

Atopicdermatitis

Idiopathicdisease

100

The Cat with Nodules

Key Questions

✓ How old was this patient when clinical signs were first recognized?(p. 3)

✓ How long has the disease been present and how did it progress? (p.3)

✓ Are there other clinical signs such as sneezing, coughing, or diar-rhea? (p. 7)

✓ Was the disease treated before? If so, which drugs were used andhow successful was treatment? (p. 8)

Differential Diagnoses The differential diagnoses depend primarily on two features: thenumber of lesions and whether draining tracts are present or not.Is there only one lesion? This increases the likelihood of neopla-sia or a kerion. Or are there multiple lesions? These may be dueto sterile inflammatory diseases, more aggressive neoplastic dis-ease, or severe infection. The presence of draining tractsincreases the likelihood of foreign bodies, severe bacterial or fun-gal infection, or sterile inflammatory disease.

In a cat with nodules, history taking and clinical examinationare followed by microscopic evaluation of impression smears (ifdraining tracts are present) and aspirates (in any cat with nod-ules) (p. 21). In some patients, cytology will reveal an infectiousorganism or classic neoplastic cells and thus a diagnosis. In mostpatients, cytology will aid in further limiting the list of differen-tial diagnoses, but a biopsy (p. 38) will be necessary to reach adiagnosis. With nodular lesions, a complete excision of one ormore nodules should be performed. If draining tracts are presentand/or cytology indicates possible infection, a tissue culture maybe useful as well (p. 43).

The differential diagnoses for feline nodules are listed in Table 2-11.

101

Tab

le 2

-11

Dif

fere

nti

al D

iag

no

ses,

Co

mm

on

ly A

ffec

ted

Sit

es,

and

Rec

om

men

ded

Dia

gn

ost

ic T

ests

in

a C

at w

ith

No

du

les

DIS

EA

SE

CO

MM

ON

LYA

FFEC

TED

SIT

ES

TR

EA

TM

EN

TP

RO

GN

OSIS

Neo

plas

ia*

Surg

ical

exc

isio

n an

d/or

tum

orsp

ecifi

c th

erap

yPo

or t

o ex

celle

nt d

epen

ding

on

the

indi

vidu

al t

umor

.

Goo

d

Fair

Fair

wit

h co

mpl

ete

exci

sion

; gua

rded

,if

this

is n

ot p

ossi

ble.

Fair

wit

h ap

prop

riat

e su

rgic

alap

proa

ch

Abs

cess

es(c

ause

d by

bite

wou

nds o

r for

-ei

gn b

odie

s)

Opp

ortu

nist

ic m

ycob

acte

rial

infe

ctio

n* (

ubiq

uito

us, f

acul

ta-

tivel

y pa

thog

enic

org

anism

ssu

ch a

s Myc

obac

teria

fortu

itum

,M

. che

lone

i, M

. sm

egm

atis,

caus

e le

sions

afte

r tra

umat

icim

plan

tatio

n in

to su

bcut

aneo

ustis

sue)

Cry

ptoc

occo

sis*

(unc

omm

on in

fect

ion

ofso

met

imes

imm

unoc

ompr

o-m

ised

hos

t w

ith

ubiq

uito

us,

sapr

ophy

tic,

yea

st-l

ike

fung

usC

rypt

ococ

cus

neof

orm

ans)

Bac

teri

al p

seud

omyc

etom

a(n

onbr

anch

ing

bact

eria

such

as

coa

gula

se-p

osit

ive

Stap

hylo

cocc

i im

plan

ted

bytr

aum

a fo

rm g

rain

s of c

ompa

ctco

loni

es su

rrou

nded

by

pyo-

gran

ulom

atou

s inf

lam

mat

ion;

rare

dis

ease

)

Ant

imyc

otic

ther

apy

with

azo

les

and/

or a

mph

oter

icin

B

(p. 1

31)

Com

plet

e su

rgic

al e

xcisi

on, p

ost-

surg

ical

ant

ibac

teria

l tre

atm

ent

(p. 1

18)

Var

ies

wit

h in

divi

dual

neo

plas

tic

dise

ases

Fluc

tuat

ing

nodu

les

mos

t co

m-

mon

ly a

roun

d ne

ck, s

houl

ders

,an

d ta

ilbas

e

Non

heal

ing

ulce

rate

d no

dule

sw

ith

drai

ning

tra

cts

pred

omin

ant-

ly in

the

abd

omin

al o

r in

guin

alar

ea (

Figu

res

2-58

and

2-5

9).

Upp

er r

espi

rato

ry, c

utan

eous

, CN

S,an

d oc

ular

sig

ns. F

irm

sw

ellin

g ov

erth

e br

idge

of t

he n

ose

(Fig

ure

2-60

), p

apul

es, n

odul

es, u

lcer

s an

ddr

aini

ng t

ract

s. N

ose,

lips

, and

cla

wbe

ds m

aybe

affe

cted

.

Firm

nod

ules

wit

h dr

aini

ng fi

stul

ae(F

igur

e 2-

61)

Wid

e su

rgic

al e

xcis

ion

follo

wed

by c

ombi

nati

on a

ntim

icro

bial

ther

apy

(p. 1

31)

Surg

ical

dra

inag

e, a

ntib

acte

rial

trea

tmen

t (p

. 118

)

102

Tab

le 2

-11

con

tin

ued

DIS

EA

SE

CO

MM

ON

LYA

FFEC

TED

SIT

ES

TR

EA

TM

EN

TP

RO

GN

OSIS

Eum

ycot

ic m

ycet

oma

(ubi

quit

ous

soil

sapr

ophy

tes

caus

e di

seas

e th

roug

h w

ound

cont

amin

atio

n; r

are

dise

ase)

Wid

e su

rgic

al e

xcis

ion

follo

wed

by

anti

myc

otic

the

rapy

(p.

131

)ba

sed

on in

vit

ro s

usce

ptib

ility

test

ing.

Fair

to

guar

ded

depe

ndin

g on

sur

gi-

cal e

xcis

ion.

Fair

Gua

rded

to

grav

e

Gua

rded

Gua

rded

Felin

e Le

pros

y*(p

resu

mab

ly tr

ansm

issio

n of

an

inco

mpl

etel

y ch

arac

teriz

edm

ycob

acte

rium

that

is d

iffic

ult

to c

ultu

re th

roug

h bi

te w

ound

sfro

m ra

ts; r

are

dise

ase

in v

eter

i-na

ry d

erm

atol

ogy)

Act

inob

acill

osis*

(Ora

l com

men

sal a

erob

icA

ctin

obac

illus

lign

eries

iiis

trau

-m

atic

ally

impl

ante

d, o

ften

thro

ugh

bite

wou

nds;

rare

dis-

ease

in v

eter

inar

y de

rmat

olog

y)

His

topl

asm

osis

(unc

omm

on in

fect

ion

wit

hdi

mor

phic

, sap

roph

ytic

soi

lfu

ngus

Hist

opla

sma

caps

ulat

um;

very

rar

e di

seas

e in

vet

erin

ary

derm

atol

ogy)

Noc

ardi

osis

*(N

ocar

dia

spp.

are

soi

l sap

ro-

phyt

es t

hat

caus

e re

spir

ator

y,cu

tane

ous,

or

diss

emin

ated

infe

ctio

ns; v

ery

rare

dis

ease

inve

teri

nary

der

mat

olog

y)

Ant

imyc

otic

ther

apy

with

azo

les,

poss

ibly

in c

ombi

natio

n w

itham

phot

eric

in B

(p.

131

)

Surg

ical

dra

inag

e, a

ntib

acte

rial

ther

apy

base

d on

in v

itro

susc

epti-

bilit

y te

stin

g.

Nod

ules

wit

h dr

aini

ng t

ract

s an

dsc

ar t

issu

e. G

rain

s va

ry in

siz

e,sh

ape,

and

col

or.

Sing

le o

r mul

tipl

e, n

onpa

infu

l and

nonp

ruri

tic

nodu

les o

n he

ad a

ndlim

bs; s

omet

imes

ulc

ers a

nd fi

stul

aear

e pr

esen

t (Fi

gure

2-6

2 A

and

B)

Thi

ck-w

alle

d ab

sces

ses

of t

hehe

ad, m

outh

, and

lim

bs d

isch

arg-

ing

thic

k pu

s w

ith

soft

yel

low

gran

ules

.

Papu

les,

nodu

les,

ulce

rs, a

nd d

rain

-in

g tr

acts

wit

h co

ncur

rent

ano

rex-

ia, w

eigh

t lo

ss, a

nd fe

ver;

dysp

nea

and

ocul

ar d

isea

se

Ulc

erat

ed n

odul

es a

nd a

bsce

sses

,of

ten

wit

h dr

aini

ng t

ract

s, on

the

limbs

and

ven

tral

abd

omen

Surg

ical

exc

isio

n or

dra

inag

e an

dlo

ng-t

erm

ant

ibac

teri

al t

hera

pyw

ith

stre

ptom

ycin

, chl

oram

phen

i-co

l, so

dium

iodi

de o

r te

trac

yclin

es(p

. 118

, 121

)

Surg

ical

exc

isio

n, c

ombi

nati

onan

tibi

otic

the

rapy

(p.

119

)

103

Phae

ohyp

hom

ycos

is*

(wou

nd c

onta

min

atio

n by

ubiq

uito

us s

apro

phyt

ic fu

ngi

wit

h pi

gmen

ted

hyph

ae; v

ery

rare

dis

ease

in v

eter

inar

y de

r-m

atol

ogy

Wid

e su

rgic

al e

xcis

ion

follo

wed

by a

ntim

ycot

ic t

hera

py (

p. 1

31)

base

d on

in v

itro

sus

cept

ibili

tyte

stin

g.

Gua

rded

Fair,

if r

ecog

nize

d an

d tr

eate

dpr

ompt

ly.

Fair

Goo

d

Fair

Plag

ue(i

nfec

tion

with

Yer

sinia

pes

tisby

inha

latio

n of

org

anism

or

thro

ugh

wou

nd c

onta

min

atio

nor

flea

bite

s; ve

ry ra

re d

iseas

e in

vete

rinar

y de

rmat

olog

y)Zo

onos

is: S

prea

d th

roug

h tr

ans-

miss

ion

of in

fect

ed fl

eas,

pres

-en

tatio

n of

infe

cted

kill

edro

dent

s, or

dire

ct in

fect

ion!

Spor

otri

chos

is*

(cau

sed

by u

biqu

itou

s di

mor

-ph

ic fu

ngal

sap

roph

yte

Spor

othr

ix s

chen

kiit

hat

infe

cts

wou

nds;

unc

omm

on d

isea

se in

vete

rina

ry d

erm

atol

ogy)

Zoon

osis

: Tra

nsm

issi

on t

ohu

man

s th

roug

h co

ntac

t w

ith

an u

lcer

ated

wou

nd

easi

ly p

ossi

ble!

Ster

ile g

ranu

lom

atou

s an

dpy

ogra

nulo

mat

ous

dise

ase

(unk

now

n pa

thog

enes

is)

Ster

ile p

anni

culit

is(u

nkno

wn

path

ogen

esis

)

Dox

ycyc

line

/ Nia

cina

mid

e (p

. 121

), im

mun

osup

pres

sive

ther

apy

(p. 1

41),

may

res

olve

spon

tane

ousl

y

Surg

ical

exc

ision

Oft

en s

olit

ary

subc

utan

eous

nod

-ul

es o

n no

se, t

runk

, or

extr

emit

ies

Hig

h fe

ver,

depr

essi

on, a

nore

xia,

and

absc

esse

s typ

ical

ly o

n th

e fa

ceor

lim

bs in

the

bubo

nic

form

.Se

ptic

emic

and

pne

umon

ic fo

rms

also

exi

st.

Mul

tipl

e no

dule

s or

ulc

erat

edpl

aque

s on

the

hea

d, d

ista

l lim

bs,

tailb

ase

(Fig

ure

2-63

). A

nore

xia,

leth

argy

, fev

er, a

nd d

epre

ssio

npo

ssib

le c

oncu

rren

tly

Firm

, pai

nles

s, no

npru

riti

c de

rmal

papu

les,

plaq

ues,

and

nodu

les

typi

-ca

lly o

n he

ad a

nd p

inna

e

Solit

ary

nodu

les

on v

entr

al r

ump

Ant

imyc

otic

the

rapy

wit

h io

dide

sor

azo

les

(p. 1

31)

Flea

con

trol

(p.

136

), d

rain

ing

ofab

sces

ses,

anti

bact

eria

l the

rapy

wit

h te

trac

yclin

e, s

trep

tom

ycin

,or

chl

oram

phen

icol

(p.

118

)

104

Tab

le 2

-11

con

tin

ued

DIS

EA

SE

CO

MM

ON

LYA

FFEC

TED

SIT

ES

TR

EA

TM

EN

TP

RO

GN

OSIS

Tube

rcul

osis

*(v

ery

rare

in s

mal

l ani

mal

der

-m

atol

ogy;

pre

dom

inan

tly

resp

i-ra

tory

and

dig

esti

ve le

sion

s)

Com

bina

tion

ant

imic

robi

al

ther

apy,

freq

uent

eut

hana

sia

(pub

lic h

ealt

h co

ncer

ns).

Poor

Insi

diou

s ul

cers

, pla

ques

, and

nod

-ul

es o

n he

ad, n

eck,

and

lim

bs d

is-

char

ging

yel

low

-gre

en p

us w

ith

unpl

easa

nt o

dor.

Figu

re 2

-58

A 5

-yea

r-ol

d ca

stra

ted

DSH

wit

h no

dule

s an

ddr

aini

ng t

ract

s re

sult

ing

from

aty

pica

l myc

obac

-te

ria.

(C

ourt

esy

of

Dr.

Sony

a B

ette

nay.

)

Figu

re 2

-59

Dra

inin

g tr

acts

due

to

atyp

ical

myc

obac

teri

ain

a 3

-yea

r-ol

d ca

stra

ted

DS

H.

Figu

re 2

-60

Nas

al s

wel

ling

caus

ed b

ycr

ypto

cocc

osis

in a

6-y

ear-

old

fem

ale

dom

esti

c lo

ng-

hai

r ca

t. (

Cou

rtes

y of

Dr.

Th

ierr

y O

livry

.)

105

Figu

re 2

-61

Pse

udom

ycet

oma

in a

Per

sian

cat

. (C

ourt

esy

of D

r. P

eter

Ih

rke.

)

Figu

re 2

-62B

Clo

seup

of f

elin

e le

pros

yin

a D

SH

. (C

ourt

esy

ofD

r. P

eter

Ih

rke.

)

Figu

re 2

-62A

Felin

e le

pros

y in

aD

SH

. (C

ourt

esy

of

Dr.

Pet

er I

hrk

e.)

Figu

re 2

-63

Nas

al u

lcer

atio

n in

a

2-ye

ar-o

ld c

astr

ated

DS

Hw

ith

spo

rotr

ich

osis

.

106

Figure 2-64 The Cat with Nodules

Bacterial infection

Cytology

Antibacterial treatment(p. 118)

Biopsy (p. 38), culture (p. 32)(48 hours post antibacterial

treatment)

Biopsy (p. 38), culture (p. 32)

No resolution Resolution

(p. 21)

No microorganisms,otherwise inconclusive

Diagnostic result Neutrophils and cocci,otherwise inconclusive

107

The Patient with Otitis ExternaOtitis externa may be seen with many diseases in conjunctionwith other clinical signs, which are helpful in the formulation ofa list of differential diagnoses. This discussion is the approach tothe dog with otitis externa and no other symptoms.

It is important to differentiate between predisposing, primary,and perpetuating factors in the pathogenesis of otitis externa.Predisposing factors are independent from the underlying diseaseand alone will not cause disease, but will facilitate the patholog-ic process. Conformation, including dense hair in the ear canal,a long and narrow ear canal, pendulous ears, and climate-relatedseasonal factors such as increased temperature and humidity areexamples of predisposing factors. Complicating factors occuronly after the primary pathologic process has begun, but contin-ue to be a problem after the primary disease has been successfullyidentified and treated. Examples are otitis media, bacterial orfungal infections, and chronic proliferative changes due toinflammation. These complicating factors need to be treatedindependently. The most common primary factors are listed inTable 2-12.

Key Questions

✓ How old was this patient when clinical signs were first recognized?(p. 3)

✓ Is the disease seasonal? (p. 3)

✓ What do you feed the animal? Was a special diet used in the past?(p. 7)

✓ Are there any other animals in the household? (p. 8)

✓ Was the disease treated before? If so, which drugs were used andhow successful was treatment? (p. 8)

✓ When was the last medication given? (p. 9)

108

Tab

le 2

-12

Dif

fere

nti

al D

iag

no

ses,

Im

po

rtan

t C

linic

al C

lues

, R

eco

mm

end

ed D

iag

no

stic

Tes

ts,

Trea

tmen

t O

pti

on

s, a

nd

Pro

gn

osi

s in

a P

atie

nt

wit

h O

titi

s Ex

tern

a

DIS

EA

SE

CO

MM

EN

TSD

IAG

NO

STIC

TESTS

TR

EA

TM

EN

TP

RO

GN

OSIS

Ato

py*

(hyp

erse

nsit

ivit

y to

aer

o-al

lerg

ens

such

as

polle

ns,

hous

e du

st m

ites

, or

mol

dsp

ores

). (

Figu

re 2

-65)

Dia

gnos

is b

ased

on

hist

ory,

phys

ical

exa

min

atio

n, a

ndru

ling

out

diffe

rent

ial d

iag-

nose

s. In

trad

erm

al s

kin

test

or s

erum

tes

t fo

r al

lerg

en-

spec

ific

IgE

(p. 4

2) id

enti

fyof

fend

ing

alle

rgen

s an

dal

low

form

ulat

ion

ofim

mun

othe

rapy

.

Alle

rgen

-spe

cific

imm

uno-

ther

apy

(p. 1

23),

ant

i-hi

stam

ines

(p.

125

),es

sent

ial

fatt

y ac

ids (

p. 1

28),

glu

coco

rti-

coid

s (p.

129

),

topi

cal g

luco

cort

icoi

ds.

Goo

d fo

r w

ell-

bein

g of

the

pati

ent

wit

h co

n-ti

nued

man

agem

ent,

guar

ded

for

cure

.

Ant

ipar

asit

ic a

gent

s su

ch a

siv

erm

ecti

n (p

. 133

) sy

stem

i-ca

lly, a

ltho

ugh

man

ypa

tien

ts w

ill r

espo

nd t

o to

p-ic

al m

itic

idal

the

rapy

Ant

ipar

asit

ic a

gent

s (p

. 133

)

Avo

idan

ce, a

ntih

istam

ines

(p

. 125

), e

ssen

tial f

atty

aci

ds(p

. 128

), g

luco

cort

icoi

ds

(p. 1

29),

topi

cal g

luco

cort

i-co

ids.

Exce

llent

Exce

llent

, if o

ffend

ing

prot

ein(

s) is

(ar

e) id

en-

tifie

d an

d av

oide

d; o

th-

erw

ise fa

ir w

ith c

ontin

-ue

d m

anag

emen

t. Po

orch

ance

of c

ure.

Rem

oval

Exce

llent

Exce

llent

Oto

dect

es c

ynot

isin

fest

a-ti

on (

very

com

mon

cau

se,

part

icul

arly

in y

oung

ani

-m

als a

nd c

ats)

Fore

ign

body

Scab

ies

(a h

ighl

y co

ntag

ious

dis-

ease

cau

sed

by S

arco

ptes

scab

iei v

ar. c

anis

in d

ogs

and

Not

oedr

es c

atii

n ca

ts)

Food

adv

erse

reac

tion

(may

or m

ay n

ot b

e al

ler-

gic;

com

mon

ly a

reac

tion

agai

nst a

pro

tein

, rar

ely

anad

ditiv

e; c

linic

ally

indi

s-tin

guish

able

from

ato

py)

Supe

rfici

al sk

in sc

rapi

ngs

(p. 2

6), s

arco

ptes

trea

tmen

ttr

ial (

p. 4

9).

Elim

inat

ion

diet

(p.

46)

In s

ome

pati

ents

a s

easo

nal

cond

itio

n; u

nila

tera

l oti

tis

exte

rna

may

be

caus

ed b

yat

opy

Cof

fee

grou

nds

appe

aran

ce o

fde

bris

in t

he e

ar c

anal

s

Typi

cally

uni

late

ral a

nd o

fac

ute

onse

t

Edge

s an

d la

tera

l asp

ects

of

pinn

ae a

ffect

ed a

s w

ell a

s (o

rw

orse

tha

n) t

he c

anal

(Fig

ure

2-66

).

Uni

late

ral o

titi

s ex

tern

am

aybe

see

n w

ith

food

adve

rse

reac

tion

s

Oto

scop

ic e

xam

inat

ion

Oto

scop

ic e

xam

inat

ion.

Mic

rosc

opic

eva

luat

ion

ofde

bris

from

ear

swab

s sus

-pe

nded

in m

iner

al o

il; m

iti-

cida

l tre

atm

ent t

rial

(p. 4

9)

109

Hyp

erad

reno

cort

icism

*(s

pont

aneo

us o

r idi

opat

h-ic

. The

spon

tane

ous f

orm

is an

exc

essiv

e pr

oduc

tion

of g

luco

cort

icoi

ds e

ither

due

to a

mic

road

enom

a or

mac

road

enom

a of

the

pitu

itary

gla

nd (

PDH

,85

%)

or d

ue to

adr

enoc

or-

tical

neo

plas

ms i

n 15

%)

Seru

m b

ioch

emis

try

(SA

P↑↑,

cho

lest

erol

↑,

ALT

↑, g

luco

se ↑

, ure

a ↓)

,he

mog

ram

s (l

euko

cyto

sis,

neut

roph

ilia,

lym

phop

enia

and

eosi

nope

nia)

, uri

naly

sis

(spe

cific

gra

vity

↓, c

orti

-so

l:cre

atin

ine

rati

o ↑)

, rad

i-og

raph

s (h

epat

omeg

aly,

oste

opor

osis

, min

eral

izat

ion

of a

dren

al g

land

s), l

ow-

dose

dex

amet

haso

ne s

up-

pres

sion

tes

t, A

CT

H a

ssay

s,ul

tras

onog

raph

y (a

dren

algl

and

size

↑),

AC

TH

sti

m-

ulat

ion

test

Iatr

ogen

ic fo

rm: d

isco

ntin

uegl

ucoc

orti

coid

adm

inis

tra-

tion

. Idi

opat

hic

form

: o,p

´-D

DD

(mit

otan

e), k

etoc

ona-

zole

for P

DH

(p

. 131

), su

rgic

al re

mov

al

of a

ffect

ed g

land

for a

dren

o-co

rtic

al n

eopl

asia

App

roxi

mat

ely

60%

of

dogs

wit

h ad

rena

ltu

mor

s wer

e re

port

edto

surv

ive

adre

nale

cto-

my

and

the

post

oper

a-ti

ve p

erio

d. T

he a

ver-

age

life

expe

ctan

cy w

as36

mon

ths.

Adr

enal

aden

ocar

cino

mas

hav

ea

bett

er p

rogn

osis

than

aden

omas

. T

he li

fesp

an o

f dog

s wit

h PD

Htr

eate

d m

edic

ally

ave

r-ag

ed 3

0 m

onth

s wit

hso

me

dogs

livi

nglo

nger

than

10

year

san

d ot

hers

onl

y da

ys.

Imm

unos

uppr

essi

on

(p. 1

41)

Surg

ical

exc

isio

n (v

erti

cal

or c

ompl

ete

abla

tion

of t

heea

r ca

nal)

Goo

d, i

f co

mpl

etel

yex

cise

d an

d no

met

asta

ses

Fair

wit

h ap

prop

riat

etr

eatm

ent,

poo

r fo

rcu

re (

exce

pt d

rug-

indu

ced

pem

phig

us)

Pem

phig

us fo

liace

us*

(im

mun

e-m

edia

ted

skin

dise

ase

char

acte

rize

d by

intr

aepi

derm

al p

ustu

le fo

r-m

atio

n du

e to

pem

phig

usan

tibo

dies

aga

inst

ant

igen

sin

the

inte

rcel

lula

r con

-ne

ctio

ns. M

ay b

e dr

ug-

indu

ced

or p

aran

eopl

asti

c)

Neo

plas

ia*

(cer

umin

ous g

land

ade

no-

mas

and

ade

noca

rcin

o-m

as–b

oth

type

s in

cats

,th

e fo

rmer

mor

e co

mm

onin

dog

s)

Oto

scop

ic e

xam

inat

ion

Subt

le c

linic

al s

igns

may

be

over

look

ed (

see

tabl

e 2-

5).

Com

plet

e re

spon

se t

o th

erap

yof

sec

onda

ry e

ar in

fect

ion

Inne

r su

rfac

e of

pin

nae

typi

-ca

lly w

orse

tha

n ca

nals

(Fig

ure

2-67

)

Uni

late

ral,

olde

r an

imal

s

Cyt

olog

y (p

. 21)

, bio

psy

(p. 3

8)

110

Tab

le 2

-12

con

tin

ued

DIS

EA

SE

CO

MM

ON

LYA

FFEC

TED

SIT

ES

DIA

GN

OSTIC

TESTS

TR

EA

TM

EN

TP

RO

GN

OSIS

Hyp

othy

roid

ism

(lym

phoc

ytic

thy

roid

itis

,pr

esum

ably

aut

oim

mun

e,or

idio

path

ic t

hyro

idne

cros

is w

hich

may

be

end-

stag

e ly

mph

ocyt

icth

yroi

diti

s)

Seru

m b

ioch

emis

try

(SA

P↑, c

hole

ster

ol ↑

, ALT

↑), h

emog

ram

s (a

nem

ia),

thyr

oid

test

s (f

ree

T4,

tot

alT

4, fr

ee T

4 by

equ

ilibr

ium

dial

ysis

, TSH

ass

ays,

TSH

stim

ulat

ion

test

, TR

H s

tim

-ul

atio

n te

st)

Hor

mon

e re

plac

emen

tth

erap

y w

ith

levo

thyr

oxin

e(p

. 144

)

Goo

d, a

ltho

ugh

not

all p

atie

nts

stay

inco

mpl

ete

and

con-

stan

t re

mis

sion

desp

ite

adeq

uate

sup

-pl

emen

tati

on.

Ear

clea

ners

, ret

inoi

ds,

cort

icos

tero

ids

Fair

to

guar

ded

for

wel

l-be

ing;

poo

r fo

r cu

re

Idio

path

ic s

ebor

rhea

*(p

rim

ary

kera

tini

zati

onde

fect

as

auto

som

al r

eces

-si

ve t

rait

wit

h de

crea

sed

epid

erm

al c

ell r

enew

alti

me

and

thus

hyp

erpr

olif-

erat

ion

of e

pide

rmis

, seb

a-ce

ous

glan

ds, a

nd fo

llicu

-la

r in

fund

ibul

um s

econ

d-ar

y to

infla

mm

atio

n,en

docr

ine

dise

ase,

or

nutr

itio

nal d

efic

ienc

ies)

Subt

le o

ther

clin

ical

sig

nsm

ay b

e ov

erlo

oked

(se

e Ta

ble

2-5)

. Com

plet

e re

spon

se t

oth

erap

y of

sec

onda

ry e

arin

fect

ion

Exce

ssiv

e w

ax fo

rmat

ion

even

wit

h to

pica

l med

icat

ion.

Bio

psy

(p. 3

8)

111

Figu

re 2

-65

Pin

nal

ery

them

a, s

calin

g, a

nd

ero-

sion

s in

a W

est

Hig

hla

nd

Wh

ite

Ter

rier

wit

h a

topy

(C

ourt

esy

of

Dr.

Son

ya B

ette

nay

).

Figu

re 2

-67

Pin

nal

oti

tis

in a

2-

year

-old

, mal

e W

hip

pet

wit

hpe

mph

igus

fol

iace

us (

Cou

rtes

yof

Dr.

Son

ya B

ette

nay

).

Figu

re 2

-66

Pin

nal

sca

ling

and

crus

tin

g in

a m

ale

Gre

at D

ane

wit

h s

ca-

bies

(C

ourt

esy

of D

r. S

onya

Bet

ten

ay).

112

Figure 2-68 Identification of the Primary Disease in the Patient

with Otitis Externa

Young animal Older animal

Diagnostic

Otoscopic examination

Further testingor treatment as

indicated

Inflammationand debrisMass or

foreign body

Surgical or manual removal

Nondiagnostic

Depending on patient and owner

Elimination diet(p.46) and antimicrobial

treatment (p. 118)

Remission

Rechallenge

Biopsy (p. 38)

No changeRelapse

Adverse foodreaction

Monitoring Relapselater on

Atopy

Intradermal skintesting, serum lgE

testing (p. 42)

Thyroid testing, urinecortisol creatinine ratio

post antimicrobial treatment (p. 118)

113

Cytology is essential in any dog or cat with otitis externa; exami-nation must be separate in the left and right ear canals as infec-tive microorganisms may be different from one ear to the other.In some animals, particularly in patients with chronic long-standing otitis externa and concurrent otitis media, organisms inthe middle ear may differ from the those isolated in the externalear. Antimicrobial treatment in the ear canal is most effectivetopically and determined by cytology (p. 21) and in vitro suscep-tibility (p. 42 and 46). Repeat cytology examinations duringtreatment is essential and changes in the otic flora may necessi-tate changing medications.

Otitis media is best treated with systemic medication. Many dogswith chronic otitis externa and otitis media may not respond totreatment because of severe accumulation of purulent or waxymaterial in the ear canals. An ear flush under anesthesia may beneeded followed by a new attempt of topical and concurrent sys-temic therapy. The tympanum may rupture prior to flushing orduring flushing because in an inflamed ear the tympanum ismuch more fragile than normal. Frequently there are few alter-natives for antimicrobial treatment in these patients. Sometimesthey may have to receive potentially ototoxic topical medica-tion. Be sure to discuss this possibility with owners before begin-ning therapy. Regular cytologic examinations are a preconditionfor successful management of patients with otitis externa. Theyare not specifically mentioned in Figure 2-68. Therapeutic trialsand tests for primary diseases may be influenced by concurrenttopical medication and thus must be planned, executed, andinterpreted with care. Chronic long-standing otitis externa isextremely frustrating for patients, clients, and veterinarians, andpatients may benefit from referral to a veterinary dermatologist.

114

Section 3

Treatments

115

In this section, I will summarize the most common treatmentmodalities, their formulations (which may vary in different partsof the world), indications, and doses. Given that detailed discus-sion of individual drugs, their mechanisms of action, pharmaco-kinetics, and protocols is beyond the scope of this text, furtherreading may be required. See Recommended Readings.

Drugs marked with an (*) and a colored screen are potentiallydangerous and the clinician inexperienced with these medicationsmay consider offering referral to a veterinary specialist or seekingfurther advice from a colleague with more knowledge about thatparticular agent.

Shampoo Therapy of Various SkinConditionsShampoo therapy can provide effective management of dermatoseswith both medical and cosmetic presenting complaints (Table 3-1).There are few adverse effects associated with shampoo therapy,although they are recognized. However, shampoo therapy is sympto-matic treatment; it rarely "cures" a dermatosis.

Prescribing a shampoo involves selecting the proper shampoo for boththe dermatosis and the client. Shampoo manufacturers have under-taken considerable research and development in order to produce for-mulations, which lather well, have an appealing smell, offer little irri-tation, and serve their intended purposes.

In addition to selecting the appropriate shampoo, the veterinarian'sinstructions will have a significant impact on the efficacy. The fre-quency of bathing and duration of skin contact time will influencethe obtained result. A 10-minute contact time is generally recom-mended. This is a long time for the owner of a fidgety, shivering dogto wait and it will frequently be cut short! Techniques to improvecontact time include:

✓ Take a clock into the bathing area and time 10 minutes accurately.

✓ Use the time for patting and bonding.

116

✓ Massage the skin for the full 10 minutes; it will usually be enjoy-able for the dog and occupy both pet and owner.

✓ Take the dog outside to play ball or go for a walk with thesoap still on (if climate permits).

✓ Rinse the shampoo off thoroughly for at least 5 to 10 minutes.

The frequency of shampooing will vary with severity and type ofthe disease process. In general, the more severe the disease, themore frequently bathing is indicated.

The major reasons for failure of shampoo therapy are

1. lack of client compliance (frequency and/or duration of application)

2. incorrect selection of shampoo for the disease process

3. shampoo irritation

117

Tab

le 3

-1Se

lect

ed S

ham

po

o T

ypes

fo

r th

e Tr

eatm

ent

of

Skin

Dis

ease

Chl

orhe

xidi

neB

acte

rial

infe

ctio

ns.

May

als

o be

hel

pful

in d

ecre

asin

gen

viro

nmen

tal c

onta

min

atio

n in

pati

ents

wit

h fu

ngal

infe

ctio

n

q 1-

14 d

ays

q 7-

14 d

ays

q 3-

14 d

ays

q 3-

14 d

ays

q 3-

14 d

ays

q 2-

14 d

ays

q 7-

14 d

ays

q 7-

14 d

ays

Ben

zoyl

per

oxid

e

Ethy

l lac

tate

Iodi

ne

Sulfu

r

Salic

ylic

aci

d

Tar

Col

loid

al o

atm

eal

Supe

rfici

al p

yode

rma.

May

also

be

help

ful i

n de

crea

sing

envi

-ro

nmen

tal c

onta

min

atio

n in

pat

ient

sw

ith fu

ngal

infe

ctio

n

Sebo

rrhe

a sic

ca, s

ebor

rhei

c de

rmat

itis.

Sebo

rrhe

a sic

ca, s

ebor

rhei

c de

rmat

itis

Sebo

rrhe

ic d

erm

atiti

s, se

borr

hea

oleo

sa

Prur

itic

skin

dise

ase,

dry

skin

Ant

ibac

teri

al, a

ntifu

ngal

, not

inac

ti-

vate

d by

org

anic

mat

ter,

not

irri

tati

ngor

dry

ing,

may

be

used

in d

ogs

and

cats

Deg

reas

ing

(and

thu

s dr

ying

), k

era-

toly

tic,

pos

sibl

y fo

llicu

lar

flush

ing.

In

dogs

wit

h dr

y or

nor

mal

ski

n, a

moi

s-tu

rize

r m

ust

be u

sed

afte

r th

e sh

am-

poo!

May

be

irri

tati

ng, p

arti

cula

rly

inco

ncen

trat

ions

ove

r 3%

. Sho

uld

not

be u

sed

in c

ats!

May

be

dryi

ng. C

ontr

over

sial

effi

cacy

in d

iffer

ent

stud

ies

Ant

ifung

al, a

ntib

acte

rial

, vir

ucid

al,

spor

icid

al, d

egre

asin

g, b

ut a

lso

stai

ning

and

pote

ntia

lly ir

rita

ting

!

Ker

atop

last

ic a

nd k

erat

olyt

ic, a

ntib

ac-

teri

al a

nd m

ildly

ant

ifung

al.

Syne

rgis

tic

wit

h sa

licyl

ic a

cid

Ker

atol

ytic

, mild

ly a

nti-

infla

mm

ator

y,sy

nerg

isti

c ac

tion

wit

h su

lfur

Ker

atop

last

ic a

nd k

erat

olyt

ic, a

ntip

ru-

riti

c an

d de

grea

sing

. In

dogs

wit

h dr

yor

nor

mal

ski

n, it

nee

ds t

o be

fol-

low

ed w

ith

a m

oist

uriz

er. N

ot t

o be

used

in c

ats!

Hyd

rate

s th

e st

ratu

m c

orne

um

Supe

rfic

ial p

yode

rma

Bac

teri

al in

fect

ions

, seb

aceo

us a

deni

-ti

s, de

mod

icos

is

SH

AM

PO

OTY

PE

CO

MM

EN

TSIN

DIC

ATIO

NS

FREQ

UEN

CY

OF

AD

MIN

ISTR

ATIO

N

Treatment of BacterialInfection✓ Antibiotics are frequently used in veterinary dermatology,because many conditions are associated with secondary bacterialinfection. Dogs with chronic allergies, immune-mediated der-matoses, or endocrinopathies frequently develop secondary pyo-dermas that exacerbate these conditions and necessitate antibac-terial treatment (Table 3-2).

✓ Not all available antibiotics are useful for skin infections sothat spectrum of activity as well as pharmacology of the differentantibacterial drugs has to be considered.

�The overwhelming majority of skin infections in the dogand cat is caused by Staphylococcus intermedius. Mixed infectionscan involve organisms such as Escherichia coli or Pseudomonasaeruginosa, which usually develop concurrently with mostpatients' primary agent, S. intermedius.

�Proper dosage and proper duration are important for the suc-cess of antibacterial therapy. Antibiotics should be given for atleast 3 weeks or longer or until at least 1 week after resolution ofclinical signs. Relapses are common in patients on short coursesof pharmacotherapy or those receiving medications at lowdosages! Deep infections may take 6 to 12 weeks to resolve.

✓ Pyodermas can, at least initially, be treated empirically. If appro-priate therapy does not resolve the condition, taking a culture isindicated (p. 32).

✓ Each sample for culture and sensitivity should be accompaniedby cytologic examination and culture results interpreted in lightof the cytology, as growth of different microorganisms does notindicate necessarily that they are present in significant numbersin vivo.

118

119

Tab

le 3

-2Se

lect

ed A

nti

bio

tics

in S

mal

l An

imal

Der

mat

olo

gy

DR

UG

FORM

ULA

TIO

NC

OM

MEN

TS

AD

VER

SE

EFF

EC

TS

IND

ICA

TIO

NS

DO

GD

OSE

(D)

CA

TD

OSE

(C)

Trim

etho

prim

/ su

lfam

etho

xazo

leN

ot f

or D

ober

man

Pin

sche

rs.

Res

ista

nce

patt

ern

vari

es,

low

in E

ngla

nd a

nd t

heU

nite

d St

ates

, hig

h in

Aus

tral

ia

Ker

atoc

onju

ncti

viti

ssi

cca,

dru

g re

acti

ons

(cut

aneo

us e

rupt

ions

,po

lyar

thri

tis,

bone

mar

-ro

w s

uppr

essi

on),

hep

ato-

toxi

c, g

astr

oint

esti

nal

sym

ptom

s, fe

ver,

hypo

thy-

roid

ism

wit

h ex

tend

ed u

se

Infe

ctio

ns w

ith

gram

-po

siti

ve b

acte

ria.

M

any

gram

-neg

ativ

eor

gani

sms

of t

he fa

mily

Ent

erob

acte

riace

aear

eal

so s

usce

ptib

le

(but

not

Pse

udom

onas

aeru

gino

sa).

Ker

atoc

onju

ncti

viti

ssi

cca,

dru

g re

acti

ons

(cut

aneo

us e

rupt

ions

,po

lyar

thri

tis,

bon

e m

ar-

row

sup

pres

sion

), h

epa-

toto

xic,

gas

troi

ntes

tina

lsy

mpt

oms,

feve

r,hy

poth

yroi

dism

wit

hex

tend

ed u

se

Vom

itin

g, d

iarr

hea,

na

usea

Vom

itin

g, d

iarr

hea

(les

s co

mm

on t

han

wit

her

ythr

omyc

in)

Bac

teri

al s

uper

ficia

lpy

oder

ma

Infe

ctio

ns w

ith m

ost

gram

-pos

itive

coc

ciin

clud

ing

Stap

hylo

cocc

i.N

ocar

dia

and

Act

inom

yces

may

also

be

susc

eptib

le.

Infe

ctio

ns w

ith

gram

-po

siti

ve b

acte

ria.

Man

ygr

am-n

egat

ive

orga

n-is

ms

of t

he fa

mily

Ent

erob

acte

riace

aear

eal

so s

usce

ptib

le (

but

not

Pseu

dom

onas

aer

ug-

inos

a).

15-3

0 m

g/kg

q

12 h

(D

, C)

15 m

g/kg

q 8

hw

itho

ut fo

od

(D, C

)

20-3

0 m

g/kg

q 1

2 h

with

out f

ood

(D, C

)

15-3

0 m

g/kg

q 1

2 h

(D, C

)Tr

imet

hopr

im/

sulfa

diaz

ine

Eryt

hrom

ycin

Linc

omyc

in

Giv

e w

itho

ut fo

od.

Inex

pens

ive!

Res

ista

nce

deve

lops

rel

ativ

ely

quic

k-ly

. Do

not

adm

inis

ter

con-

curr

entl

y w

ith

terf

ena-

dine

, cyc

losp

orin

e, o

rke

taco

nazo

le

Giv

e w

ithou

t foo

d.C

ontr

aind

icat

ed in

rabb

its,

ham

ster

s, an

d gu

inea

pig

s!

5/25

mg

and

20/1

00 m

gco

ated

tabl

ets,

40 m

g/20

0 m

g, 8

0 m

g/40

0 m

g,an

d 16

0 m

g/80

0 m

gta

blet

s, 8

mg/

40 m

g/m

lsy

rup.

180

mg/

820

mg

tabl

ets,

9 m

g/41

mg/

ml s

yrup

250

mg

and

500

mg

tabl

ets,

500

mg

coat

edta

blet

s, 20

mg/

ml,

40m

g/m

l, 80

mg/

ml,

120

mg/

ml s

yrup

.

200

and

500

mg

tabl

ets,

500

mg

caps

ules

.

Not

for

Dob

erm

anP

insc

hers

.R

esis

tanc

e pa

tter

n va

ries

,lo

w in

Eng

land

and

the

Uni

ted

Stat

es, h

igh

inA

ustr

alia

Peni

cilli

n V

Not

com

mon

ly u

sed

inde

rmat

olog

y be

caus

em

ost

stra

ins

ofSt

aphy

loco

ccus

inte

rmed

ius

stra

ins

are

resi

stan

t to

peni

cilli

n

Gas

troi

ntes

tina

l sig

nsw

ith

oral

adm

inis

trat

ion,

hype

rsen

siti

vity

rea

ctio

ns

Infe

ctio

ns w

ith

Act

inom

yces

, mos

t spi

ro-

chet

es a

nd g

ram

-pos

i-ti

ve a

nd g

ram

–neg

ativ

eco

cci,

whi

ch d

o no

tpr

oduc

e pe

nici

llina

se.

Vom

itin

g, d

iarr

hea,

alle

r-gi

c re

acti

ons

Vom

itin

g, d

iarr

hea,

alle

rgic

rea

ctio

ns

Vom

itin

g, d

iarr

hea,

alle

rgic

rea

ctio

ns

Vom

itin

g an

d di

arrh

ea;

very

rar

ely

exci

tabi

lity,

tach

ypne

a or

blo

oddy

scra

sias

.

Vom

itin

g an

d di

arrh

ea,

very

rar

ely

tach

ypne

a or

bloo

d dy

scra

sias

Bac

teri

al p

yode

rma

Pyod

erm

a ca

used

by

sens

itiv

e co

cci

Supe

rfic

ial a

nd d

eep

bact

eria

l pyo

derm

as

Supe

rfic

ial a

nd d

eep

bact

eria

l pyo

derm

as

Mos

t or

gani

sms

that

caus

e sk

in d

isea

se a

rere

sist

ant

to a

mpi

cilli

nan

d am

oxyc

illin

, thu

sit

is r

arel

y in

dica

ted.

10 m

g/kg

q 6

-8 h

(D

, C)

12.5

-25

mg/

kg q

8-12

h (D

, C)

20-4

0 m

g/kg

q 8

h(D

, C)

20-3

0 m

g/kg

q

8-12

h (D

, C)

20-3

0 m

g/kg

q

8-12

h (

D, C

)

10-2

0 m

g/kg

q 8

h(D

, C)

Am

oxyc

illin

Cla

vula

nic

acid

/am

oxyc

illin

Clo

xaci

llin

Cep

hale

xin

Cef

adro

xil

In v

itro

resis

tanc

e of

Stap

hylo

cocc

i ext

rem

ely

low,

but

sens

itivi

ty in

vitr

ono

t alw

ays c

orre

latin

g w

ithre

sults

in v

ivo.

May

be

mor

e ef

ficac

ious

with

q

8 h

adm

inist

ratio

n.

Effe

ctiv

e ag

ains

t mos

tgr

am-p

ositi

ve c

occi

Use

d co

mm

only

in v

eter

i-na

ry d

erm

atol

ogy

125,

250

, 500

mg

tabl

ets,

25 m

g/m

l and

50

mg/

ml o

ral s

uspe

nsio

n.

500

mg,

750

mg,

100

0m

g ta

blet

s, 50

mg/

ml

syru

p.

12.5

/50

mg,

62.

5/25

0m

g, 1

25/5

00 m

g ta

blet

s,12

.5/5

0 m

g sy

rup

250

mg

and

500

mg

caps

ules

, 25

mg/

ml

solu

tion

500

mg,

100

0 m

gta

blet

s, 25

0 m

g,

500

mg

caps

ules

, 75

mg,

300

mg,

600

mg

tabl

ets,

50 m

g/m

l syr

up

1000

mg

tabl

ets,

50 m

g/m

l syr

up

Not

com

mon

ly u

sed

inde

rmat

olog

y be

caus

e m

ost

Stap

hylo

cocc

us in

term

ediu

sst

rain

s ar

e re

sist

ant

toam

oxyc

illin

.

120

Tab

le 3

-2 c

on

tin

ued

DR

UG

FORM

ULA

TIO

NC

OM

MEN

TS

AD

VER

SE

EFF

EC

TS

IND

ICA

TIO

NS

DO

GD

OSE

(D)

CA

TD

OSE

(C)

121

Tetr

acyc

line

Shou

ld n

ot b

e gi

ven

with

amph

oter

icin

B o

r ery

th-

rom

ycin

. In

vete

rinar

yde

rmat

olog

y us

ed fo

rim

mun

omod

ulat

ory

effe

cts

Nau

sea,

vom

iting

, disc

ol-

orat

ion

of te

eth

in p

uppi

esan

d ki

tten

s, ph

otot

oxic

reac

tions

, hep

atot

oxic

ity

In c

ombi

nati

on w

ith

niac

inam

id u

sed

for

the

trea

tmen

t of

dis

coid

lupu

s er

ythe

mat

osus

,id

iopa

thic

ony

cho-

mad

esis

.

Nau

sea,

vom

itin

g, d

isco

l-or

atio

n of

tee

th in

pup

-pi

es a

nd k

itte

ns; p

hoto

-to

xic

reac

tion

s

Skin

ras

hes,

vom

itin

g,di

arrh

ea.

Car

tilag

e er

osio

ns in

pup

-pi

es, v

omiti

ng a

nd d

iar-

rhea

. Hyp

erse

nsiti

vitie

san

d C

NS

signs

cou

ldpo

tent

ially

occ

ur.

Cry

stal

luria

may

occ

ur in

dehy

drat

ed a

nim

als

Car

tilag

e er

osio

ns in

pup

-pi

es; v

omiti

ng a

nd d

iar-

rhea

. Hyp

erse

nsiti

vitie

san

d C

NS

signs

cou

ldpo

tent

ially

occ

ur.

Cry

stal

luria

may

occ

ur in

dehy

drat

ed a

nim

als

Infe

ctio

ns w

ith

gram

-po

siti

ve c

occi

, mos

tan

aero

bic

orga

nism

s,N

ocar

dia,

Act

inom

yces

Infe

ctio

ns w

ith st

aphy

-lo

cocc

i, m

ycob

acte

ria,

mos

t gra

m-n

egat

ive

orga

nism

s

Infe

ctio

ns w

ith st

aphy

-lo

cocc

i, m

ycob

acte

ria,

mos

t gra

m-n

egat

ive

orga

nism

s

Bac

teri

al s

uper

ficia

lpy

oder

ma,

myc

obac

ter-

ial i

nfec

tion

s, d

isco

idlu

pus

eryt

hem

atos

us.

250-

500

mg/

anim

alq

8 h

(in

com

bina

-tio

n w

ith n

iaci

-na

mid

e at

250

-500

mg/

anim

al q

8 h

)(D

, C)

5-10

mg

mg/

kg

q 12

h (D

, C)

5-20

mg/

kg q

24

h(D

)5

mg/

kg q

24

h (C

)

5-15

mg/

kg q

12

h(D

, C)

2.5-

5 m

g/kg

q 2

4 h

(if u

sed

for i

mm

une-

med

iate

d di

seas

es, i

tis

com

bine

d w

ithni

acin

amid

e at

250

-50

0 m

g/an

imal

q

8 h)

(D

, C)

Dox

ycyl

ine

Clin

dam

ycin

Enro

floxa

cin

Cip

roflo

xaci

n

Do

not g

ive

conc

urre

ntly

with

cyc

losp

orin

, iro

n su

p-pl

emen

tatio

n, a

nd o

ral

diab

etic

age

nts.

Not

in im

mat

ure

anim

als!

Inef

fect

ive

agai

nst a

naer

o-bi

c or

gani

sms.

Res

istan

cem

ay o

ccur

, par

ticul

arly

toPs

eudo

mon

as.

Inef

fect

ive

agai

nst a

naer

-ob

e or

gani

sms.

Res

istan

cem

ay o

ccur

, par

ticul

arly

toPs

eudo

mon

as.

250

mg,

500

mg

caps

ules

50 m

g, 1

00 m

g, 2

00 m

gca

psul

es, 1

00 m

g/m

lpa

ste,

1 m

g/m

l, 5

mg/

ml

susp

ensi

on

75 m

g, 1

50 m

g, 3

00 m

gca

psul

es

5.7

mg,

22.

7 m

g, 5

0 m

g,68

mg,

136

mg,

150

mg

tabl

ets

100

mg,

250

mg

, 500

mg,

750

mg

coat

edta

blet

s

Als

o us

ed fo

r ef

fect

s on

cel

lsof

the

imm

une

syst

em a

ndcy

toki

ne p

rodu

ctio

n

122

Mar

boflo

xaci

nN

ot in

imm

atur

e an

imal

s!In

effe

ctiv

e ag

ains

t ana

er-

obe

orga

nism

s. R

esist

ance

may

occ

ur, p

artic

ular

ly to

Pseu

dom

onas

.

Car

tila

ge e

rosi

ons i

n pu

p-pi

es, v

omit

ing

and

diar

-rh

ea. H

yper

sens

itiv

itie

san

d C

NS

sign

s cou

ldpo

tent

ially

occ

ur.

Infe

ctio

ns w

ith

stap

hy-

loco

cci,

myc

obac

teri

a,m

ost

gram

-neg

ativ

eor

gani

sms

Loca

lized

sup

erfic

ial

bact

eria

l inf

ecti

ons,

felin

e ac

ne.

2.5-

5 m

g/kg

q 2

4 h

with

out f

ood

(D, C

)

App

ly to

affe

cted

area

s q 1

2 h,

pre

-ve

nt a

nim

al fr

omlic

king

are

a fo

r 10

min

utes

(D

, C)

Mup

iroci

n

25-m

g, 5

0-m

g, 1

00-m

g,20

0-m

g sc

ored

coa

ted

tabl

ets

2% o

intm

ent

Effe

ctiv

e ag

ains

t gr

am-

posi

tive

org

anis

ms,

part

ic-

ular

ly S

taph

yloc

occi

.

Tab

le 3

-2 c

on

tin

ued

DR

UG

FORM

ULA

TIO

NC

OM

MEN

TS

AD

VER

SE

EFF

EC

TS

IND

ICA

TIO

NS

DO

GD

OSE

(D)

CA

TD

OSE

(C)

123

Treatment of Pruritus

Allergen-specificImmunotherapy*Specific immunotherapy was introduced to veterinary medicine inthe1960s. Since then several studies have been undertaken toevaluate the efficacy of allergy shots in dogs and cats. Despite theuse of different allergens (aqueous versus aluminum-precipitated)and different protocols, the overall success rate was comparableand varied from 45% to 60% in studies with a follow-up of 1 yearor longer to 70% to 100% in studies with a shorter duration.

In specific immunotherapy, an individual is exposed to extracts ofantigens to which it has shown an allergic reaction. This exposurestarts at low concentrations that are increased gradually over timeand after reaching a maintenance dose, are either continued indef-initely or slowly tapered.

Considerations before Beginning Allergen-specific ImmunotherapyClinically and relevant to daily practice, several key issues needto be discussed with owners before they consider allergen-specificimmunotherapy or "allergy shots".

✓ The success rate: About 20% of the patients will do extremelywell and thrive with no additional therapy; 40% of the patientsdo well, even though occasional additional treatments such asantihistamines, fatty acids and/or antibiotics are needed. Ownersare happy with the improvement achieved and consider theallergy shots worthwhile, even though therapy may be lifelong.Another 20% of patients improve, but the degree of improve-ment is unsatisfactory. And in 20% of the patients therapy hasno influence on the disease process.

✓ The cost: This may vary depending on the country of practice,the dog’s allergies, the vaccines used, and the dose rates needed.Veterinary dermatologists are a good source of information forapproximate expense.

124

✓ The time to improvement: First improvement may be seen asearly as 4 weeks into therapy and as late as 12 months after start-ing the allergy shots. On average, improvement is expected afterbetween 4 and 6 months.

✓ The duration of treatment: A minority of owners may discon-tinue their dogs' immunotherapy after 2 years, with their petsbeing permanently cured and symptom free. Other dogs, however,will require lifelong therapy!

✓ The involvement: Atopic dogs are "high maintenance" and assuch need constant care, most likely at least initially regularrechecks and concurrent medication. Allergy shots are not aneasy way out but at this point the best of many available treat-ments, all of which involve long-term administration of medica-tions of some sort.

Points to Remember if You Have Patients on Immunotherapy� Glucocorticoids may be given on an occasional basis at anti-inflammatory dosage levels without interfering with therapy.

✓ Antihistamines, fatty acids, and antimicrobials do not inter-fere with immunotherapy so that they may be, and often are,used concurrently.

� If the condition of patients receiving allergy shots suddenlydeteriorates, always evaluate for infection. Yeast and bacteria arecommon complicating factors secondary to these allergies, whichcan cause dramatic increases in pruritus. Cytology (p. 21) willidentify cocci, rods, yeasts and inflammatory cells and therebyguide antimicrobial therapy.

✓ If no infection is detected, antihistamines or glucocorticoidscan be used to regulate the patient’s pruritus.

✓ If there is a regular increase in pruritus after the injection, thedose and frequency may need to be adjusted. Decreased dosesmay be helpful.

✓ If there is a regular increase in pruritus before the injectionthat is greatly improved by the injection of allergen extract, thetime interval between the injections is probably too long andneeds to be shortened. The dose may also be decreased in someof these patients without decreased efficacy.

125

✓ If there is no response to allergen-specific immunotherapyafter 4 to 6 months, I recommend that you contact your nearestveterinary dermatologist for advice while there is still sufficientvaccine left to change the dose and frequency of the injectionsby adjusting them to the needs of that particular patient. Manypatients need an approach suiting their particular requirementsand the help of a veterinarian experienced in immunotherapymay be of great benefit.

I sincerely believe that allergen-specific immunotherapy is cur-rently the best available treatment for canine atopic dermatitis,but it will only be successful in most atopic animals if ownersand veterinarians have realistic expectations and are prepared toput in significant effort over the period that sometimes extendsover many months. Only then will maximal benefit be achieved!In as much as the first months on immunotherapy may be drain-ing for owner and veterinarian, consider offering referral to aveterinary dermatologist, particularly if you are not experiencedin this therapy.

Antihistamines✓ Antihistamines are useful adjunctive agents in the manage-ment of pruritic patients. The classical antihistamines act byblocking H1-receptors. First-generation antihistamines also havean anticholinergic, sedative, and local anaesthetic effect.Second-generation antihistamines penetrate less through theblood brain barrier or have a low affinity for the brain comparedwith the action on peripheral H1-receptors. Thus they are effec-tive yet produce less sedation (Table 3-3).

✓ The advantage of antihistamines is the rare occurrence ofadverse effects. Drowsiness is the most common finding and maydecrease after 2 to 3 days of therapy. Thus, it may be worthwhilecontinuing treatment for several days before final evaluation.Less common are gastrointestinal signs. Acute poisoning follow-ing an overdose is characterized by CNS hyperexcitability. Dueto the anticholinergic properties of terfenadine and cyprohepta-dine, these drugs should not be used in patients with severe car-diovascular disease, since they may cause hypertension.

✓ The necessity of frequent administration (two to three timesdaily) and the high cost of some antihistamines limit their long-term use in many patients, especially larger dogs.

126

✓ A further shortcoming in dogs is the relatively low successrate, which varies between 5% and 30%, depending on dosageand drug used.

� Cats are much more likely to respond to antihistaminesthan dogs. However, administering oral medication on a long-term basis may be challenging in this species.

✓ If a patient responds to antihistamine therapy and the owneris willing to maintain the animal on it, antihistamines representsafe long-term treatment that is preferable to glucocorticoids!

✓ Antihistamines in humans are not used to treat present symp-toms but to prevent onset of symptoms. Thus, administrationshould not be intermittent assuming the same holds true in ani-mals.

� The potential success rate can be increased by trying severaldifferent antihistamines sequentially because patients may beresponsive to one antihistamine but not to another.

� Antihistamines have been reported to be effective in lower-ing the corticosteroid dose, even if they did not help the animalas a single therapeutic agent.

✓ Because the withdrawal time of antihistamines before anintradermal skin test is much shorter than that of glucocorti-coids, they can be used to relieve pruritus during the preparationtime where the latter are contraindicated.

127

Tab

le 3

-3Se

lect

ed A

nti

his

tam

ines

Use

d in

th

e Tr

eatm

ent

of

Smal

l An

imal

Hyp

erse

nsi

tivi

ties

DR

UG

FORM

ULA

TIO

NC

OM

MEN

TS

DO

GD

OSE

(D),

C

AT

DO

SE

(C)

Dex

chlo

rphe

nira

min

eIn

expe

nsiv

e, p

oten

tial

ly s

edat

ing

2-6

mg

q 8-

12 h

(D

),

2 m

g q

8-12

h (

C)

2-12

mg

q 12

h (

D)

2-4

mg

q 12

h (

C)

1-2

mg/

kg q

12

h (D

,C)

2 m

g/kg

q 8

-12

h (D

, C)

5-20

m q

12-

24 h

(D

)5

mg

q 12

-24

h (C

)

5-20

mg

q 1

2-24

h (

D)

5 m

g q

12-2

4 h

(C)

0.5-

1 m

g q

12 h

(D

)

30-6

0 m

g q

12 h

(D

)

2-8

mg

q 8-

12 h

(D

)2-

4 m

g q

12 h

(C

)

Chl

orph

enira

min

e

Cyp

rohe

ptad

ine

Prom

etha

zine

Hyd

roxy

zine

Lora

tidi

ne

Cet

iriz

ine

Cle

mas

tine

Terf

enad

ine

Seda

ting

Also

inhi

bits

mas

t cel

l deg

ranu

latio

n, a

nd is

tric

yclic

ant

ide-

pres

sant

and

tera

toge

nic!

!

Inhi

bits

exo

cyto

sis o

f eos

inop

hils

in h

uman

s

Enha

nces

cho

liner

gic

activ

ity o

f oth

er a

ntih

istam

ines

as t

hese

drug

s are

met

abol

ized

by sa

me

enzy

me

syst

em in

live

r and

con

-cu

rren

t adm

inist

ratio

n m

ay in

crea

se se

rum

leve

ls sig

nific

antly

.

Do

not g

ive

conc

urre

ntly

with

ket

ocon

azol

e, c

yclo

spor

ine,

aste

mizo

l, or

ery

thro

myc

in a

s the

se d

rugs

are

met

abol

ized

bysa

me

enzy

me

syst

em in

live

r and

con

curr

ent a

dmin

istra

tion

may

incr

ease

seru

m le

vels

signi

fican

tly.

2 m

g ta

blet

s, 6

mg

tabl

ets

4 m

g ta

blet

s

4 m

g ta

blet

s

10 m

g, 2

5 m

g co

ated

tab

lets

10 m

g, 2

5 m

g, 5

0 m

g ca

psul

es

10 m

g ta

blet

, 1 m

g/m

l syr

up

10 m

g co

ated

tab

lets

, 1 m

g/m

lsy

rup

1 m

g ta

blet

s, 0.

05 m

g/m

l syr

up

60 m

g, 1

20 m

g ta

blet

s, 6

mg/

ml

susp

ensio

n

Inex

pens

ive,

pot

enti

ally

sed

atin

g

Inex

pens

ive,

pot

enti

ally

sed

atin

g

Ast

emiz

ol0.

25 m

g/kg

q 2

4 h

(D, C

)10

mg

tabl

ets,

2 m

g/m

l sus

pen-

sion

Trim

epra

zine

2.5-

10 m

g q

8-12

h (

D)

2.5

mg,

5 m

g ta

blet

s

Aza

tidi

ne0.

5-2m

g q

12 h

(D

)0.

5 m

g q

12 h

(C

)1

mg

tabl

ets,

0.5

mg/

5 m

l syr

up

Foxo

fena

chin

Do

not a

dmin

ister

con

curr

ently

with

ket

ocon

azol

, itr

acon

azol

,er

ythr

omyc

in, c

yclo

spor

ine,

or t

erfe

nadi

ne30

-120

mg

q 12

h (

D)

60 m

g , 1

20 m

g, 1

80 m

g co

ated

tabl

ets

Am

itry

ptill

ine

1 m

g/kg

q 1

2 h

(D, C

)10

mg,

25

mg

tabl

ets

Do

not a

dmin

ister

con

curr

ently

with

ket

ocon

azol

, itr

acon

azol

,cy

clos

porin

e, e

ryth

rom

ycin

, or t

erfe

nadi

ne.

128

Essential Fatty Acids✓ Essential fatty acids (EFAs) are important for epidermal barrierfunction, as components of cell membranes, and as the precursorsof inflammatory mediators.

✓ Supplementation with specific EFAs, especially linoleic acid(in sunflower and safflower oil), gamma-linolenic acid (inevening primrose oil) and eicosapentanoic acid (in cold watermarine fish oil), can have anti-inflammatory effects. Linoleicacid is needed for maintenance of stratum corneum barrier func-tion, limits transepidermal water loss and is thus better suited forthe treatment of scaling (Table 3-4).

✓ Success rate of EFA therapy is relatively low in dogs, higher in cats.

✓ It may take several weeks of supplementation until clinicaleffects become evident.

✓ In essence, EFA supplementation decreases production ofinflammatory prostaglandins and leukotrienes in favor of anincreased production of noninflammatory or antiinflammatoryprostaglandins and leukotrienes.

✓ Adjunctive therapy with essential fatty acids can be beneficialin a patient with allergies.

� Fatty acids have been reported to be effective in lowering thecorticosteroid dose, even if they did not help the animal as a sin-gle therapeutic agent.

� Start with a small dose to avoid possible diarrhea and gradu-ally increase the dose.

✓ Ideal doses and w-6/w-3 ratios are a subject of continuingactive research.

Table 3-4Essential Fatty Acids and Their Doses

ESSENTIAL FATTY ACID DOSE

Eicosapentaenoic acid

Linoleic acid

20 mg/kg q 24 h

20-50 mg/kg q 24 h

129

Glucocorticoids✓ Glucocorticoids are very commonly used in the treatment ofskin conditions (Table 3-5).

✓ At anti-inflammatory dosage, they decrease inflammatory cellactivity and migration.

✓ Corticosteroids are effective in most patients with atopic diseaseand resolve the symptoms at least initially on reasonably lowdosages. Flea-allergic animals will also often respond to these drugs,although typically at slightly higher dosages.

✓ Glucocorticosteroids can be considered the treatment of choicein animals with a mild seasonal pruritus of 1 to 2 months durationthat is controlled with anti-inflammatory dosages (<1 mg/kg) ofprednisolone every other day.

✓ Every other day therapy is definitively preferred over daily drugadministration because as it is thought to lower the chances ofiatrogenic hyperadrenocorticism.

✓ I use prednisolone at anti-inflammatory doses for severely affect-ed dogs after skin testing and short term to break the itch-scratchcycle. However, the need to increase the dosage over time to con-trol the clinical signs in most of these patients, combined with thepotentially severe long-term side effects make glucocorticoids apoor long-term choice for atopic patients.

✓ Adverse effects include polyuria, polydipsia, polyphagia,increased susceptibility to infection, and other well-known symp-toms of iatrogenic hyperadrenocorticism. The most commonlyencountered infections affect the urinary tract, skin, and lungs.

✓ Drugs should always be tapered to the lowest effective dose.

� Frequently, the dose necessary to control clinical signs can bedecreased when adjunctive therapy is used. Fatty acids and antihis-tamines have been reported to be effective in lowering the corti-costeroid dose, even if they did not help the animal as a singletherapeutic agent. Regular topical therapy (e.g., shampoos) may beanother means of decreasing the need for systemic glucocorticoids.

� I recommend to the owners of my atopic patients treated withglucocorticoids the lowest possible dose, on which the animal ismildly itchy but not uncomfortable. If no pruritus is present, thedose used is too high.

� The glucocorticoid dose needed with individual patients oftenvaries seasonally.

130

Treatm

en

t o

f Fu

ng

al In

fect

ion

s A

nti

myc

oti

c ag

ents

(T

able

3-6

) ar

e u

sed

aft

er f

un

gal

infe

ctio

n i

s d

iagn

ose

d b

y p

osi

tiv

e fl

uo

resc

ence

un

der

Wo

od

’s l

amp

(p

. 3

0),

by

fun

gal

cult

ure

(p

. 3

2)

and

/or

bio

psy

(p

. 3

8).

Id

eall

y, t

reat

men

t is

co

nti

nu

edb

eyo

nd

cyt

olo

gic

reso

luti

on

(M

alas

sezi

asp

p.)

or

un

til

a n

egat

ive

cult

ure

co

nfi

rms

rem

issi

on

(d

erm

ato

ph

ytes

and

sys

tem

ic f

un

gi)

wh

ich

is

app

rox

imat

ely

2 w

eek

s p

ast

a n

egat

ive

cult

ure

an

d 4

wee

ks

pas

t cy

tolo

gic

reso

luti

on

.

Tab

le 3

-5Se

lect

ed G

luco

cort

ico

ids

and

Th

eir

Do

sag

eD

RU

GF

OR

MU

LATIO

NS

TAR

TIN

GD

OSE

Pred

niso

ne

Pred

niso

lone

Met

hylp

redn

isol

one

Dex

amet

haso

ne

Tria

mci

nolo

ne

1 m

g, 5

mg,

20

mg,

50

mg

tabl

ets

0.5-

1 m

g/kg

q 2

4-48

h (

D)

1-2

mg/

kg q

24-

48 h

(C

)

1 m

g, 5

mg,

20

mg,

25

mg,

50

mg

tabl

ets

0.5-

1 m

g/kg

q 2

4-48

h (

D)

1-2

mg/

kg q

24-

48 h

(C

)

2 m

g, 4

mg,

16

mg,

32

mg,

10

0 m

g ta

blet

s, 20

mg/

ml,

40m

g/m

l Met

. ace

tate

0.5,

1.5

, 4 m

g ta

blet

s,2

mg/

ml,

4 m

g/m

l

2 m

g, 4

mg,

8 m

g ta

blet

s, 3

mg/

ml,

10 m

g/m

l, 40

mg/

ml

0.4-

0.8

mg/

kg q

24-

48 h

ora

lly(D

), in

tram

uscu

larly

0.05

-0.1

mg/

kg q

48-

72 h

ora

lly(D

), 0

.2-0

.5 m

g/ in

tram

uscu

larly

(D);

0.1

-0.2

5 m

g/(C

),

0.05

-0.1

mg/

kg q

48-

72 h

ora

lly(D

); 0

.1-0

.2 m

g/kg

IM o

r sub

cu-

tane

ously

SC

(D

,C)D

OG

DO

SE

(D)

CA

TD

OSE

(C)

131

Tab

le 3

-6Sy

stem

ic A

nti

myc

oti

c A

gen

ts

DR

UG

FORM

ULA

TIO

NC

OM

MEN

TS

IND

ICA

TIO

NS

SID

EEFF

EC

TS

DO

GD

OSE

(D)

CA

TD

OSE

(C)

Gri

seof

ulvi

nA

dmin

iste

red

wit

h fa

tty

mea

lD

erm

atop

hyto

sis

Tera

toge

nic!

Vom

itin

g,di

arrh

ea, i

dios

yncr

atic

bone

mar

row

sup

pres

-si

on

Mal

asse

zia-

rela

ted

infe

c-ti

ons,

der

mat

ophy

tosi

s,bl

asto

myc

osis

, cry

ptoc

oc-

cosi

s, c

occi

dioi

dom

ycos

is,

spor

otri

chos

is, n

ocar

dio-

sis,

hyp

erad

reno

cort

icis

m

Mal

asse

zia

and

Can

dida

infe

ctio

ns, d

erm

atop

hy-

tose

s, s

yste

mic

myc

oses

Spor

otri

chos

is

Ano

rexi

a, n

ause

a,he

pato

toxi

city

Vom

itin

g, d

iarr

hea,

depr

essi

on, a

nore

xia,

hypo

ther

mia

, car

dio-

vasc

ular

failu

re in

cat

s;oc

ular

and

nas

al d

is-

char

ge, s

calin

g an

d dr

yco

at in

dog

s.

Ano

rexi

a, n

ause

a(q

uite

com

mon

),

vom

itin

g, d

iarr

hea,

chol

angi

ohep

atit

is

Mic

rosiz

e cr

ysta

lfo

rm: 2

5-60

mg/

kg q

12 h

, ultr

amic

rosiz

eG

ris-P

EG 2

.5-1

0m

g/kg

q 1

2 h

(D,C

)

5-10

mg/

kg

q 12

-24

h (D

,C)

40 m

g/kg

q 1

2 h

(D);

20

mg/

kg

q 12

-24

h (C

)

2.5-

10 m

g/kg

q 1

2 h

for M

alas

sezia

infe

c-tio

n (D

, C),

10

mg/

kg q

12

h fo

rde

rmat

ophy

tosis

(D

, C),

up

to 2

0m

g/kg

q 1

2 h

for

syst

emic

myc

oses

(D, C

), a

nd h

yper

a-dr

enoc

ortic

ism (

D)

Ket

ocon

azol

e

Itra

cona

zole

Pota

ssiu

m io

dide

Adm

inist

er w

ith fo

od! I

fgi

ven

conc

urre

ntly

with

cycl

ospo

rin, s

ome

antih

ist-

amin

es, p

heny

toin

, or o

ral

antid

iabe

tic a

gent

s, th

edr

ug d

oses

may

hav

e to

be

decr

ease

d. R

ifam

pin

may

decr

ease

itra

cona

zole

seru

m le

vels.

Giv

e w

ith fo

od

125

mg

and

500

mg

tabl

ets

200

mg

tabl

et

100

mg

caps

ule

Adm

inis

ter

wit

h fo

od!

Incr

ease

s bl

ood

leve

ls o

fcy

clos

pori

n, p

heny

toin

,an

d so

me

anti

hist

amin

es.

Rifa

mpi

n m

ay d

ecre

ase

keto

cona

zole

ser

um le

vels

.W

ith

high

-dos

e th

erap

y, a

slow

incr

ease

ove

r se

vera

lda

ys m

ay m

inim

ize

adve

rse

effe

cts.

132

Tab

le 3

-6 c

on

tin

ued

DR

UG

FORM

ULA

TIO

NC

OM

MEN

TS

IND

ICA

TIO

NS

SID

EEFF

EC

TS

DO

GD

OSE

(D)

CA

TD

OSE

(C)

Terb

inaf

ine

Fair

ly n

ew a

nd c

ostl

ydr

ug a

t ti

me

of w

riti

ng,

limit

ed p

rom

isin

g in

for-

mat

ion

avai

labl

e.

Der

mat

ophy

tosi

sV

omit

ing

Bla

stom

ycos

is, h

isto

plas

-m

osis

, cry

ptoc

occo

sis,

oral

can

didi

asis

In c

ombi

nati

on w

ith

keto

cona

zole

for

blas

to-

myc

osis

, his

topl

asm

osis

,co

ccid

iom

ycos

is a

ndsp

orot

rich

osis

, in

com

bi-

nati

on w

ith

flucy

tosi

nefo

r cr

ypto

cocc

osis

and

cand

idia

sis

Nep

hrot

oxic

ity,

ane

-m

ia, p

hleb

itis

,hy

poka

lem

ia

Vom

itin

g, d

iarr

hea,

naus

ea, h

epat

otox

icit

y

10-3

0 m

g/kg

q 2

4 h

for 2

-4 w

eeks

(D

,C)

0.5

mg/

kg I

V in

5% d

extr

ose

ever

yot

her

day

(D),

0.15

mg/

kg I

V in

5% d

extr

ose

ever

yot

her

day

(C).

Safe

r is

sub

cuta

-ne

ous

adm

inis

tra-

tion

of 0

.5 m

g/kg

,am

phot

eric

in is

in40

0 m

l of 0

.45%

salin

e co

ntai

ning

2.5%

dex

tros

e q

3-4

d’s

to a

tot

alcu

mul

ativ

e do

se

of 1

0-25

mg/

kg.

2.5-

5 m

g/kg

q

12 h

(D

); 2

.5-1

0m

g/kg

q 1

2 h

(C)

Fluc

onaz

ole

Am

pote

rici

n B

*R

elat

ivel

y to

xic,

thus

trea

tmen

t is d

ange

rous

and

refe

rral

may

be

con-

sider

ed. I

ncom

patib

le w

ithsa

line

and

lact

ated

Rin

ger’s

solu

tion

and

othe

r dru

gs

250

mg

tabl

et

50-m

g, 1

00-m

g, 1

50-

mg,

200

-mg

caps

ules

50-m

g dr

ysu

bsta

nce/

bott

le

Pene

trat

es in

to c

entr

alne

rvou

s sy

stem

(C

NS)

and

saliv

a w

ell.

Dos

ene

eds

to b

e de

crea

sed

inpa

tien

ts w

ith

rena

l ins

uf-

ficie

ncy.

Rifa

mpi

n m

ayde

crea

se fl

ucon

azol

ese

rum

leve

ls. I

ncre

ases

bloo

d le

vels

of

cycl

ospo

rine

, phe

nyto

inan

d so

me

anti

hist

amin

es.

133

Ect

op

ara

siti

cid

al A

gen

tsW

hen

tre

atin

g p

atie

nts

wit

h e

cto

par

asit

es,

env

iro

nm

ent

and

co

nta

ct a

nim

als

hav

e to

be

con

sid

ered

as

wel

l.E

nv

iro

nm

enta

l co

nta

min

atio

n i

s si

gnif

ican

t w

ith

fle

as a

nd

ch

igge

rs (

Tro

mbi

cula

, N

eotr

ombi

cula

, W

alch

ia)

and

po

ssib

ly w

ith

Che

ylet

iella

. C

on

tact

an

imal

s m

ust

be

trea

ted

fo

r al

l ec

top

aras

ites

ex

cep

t D

emod

exan

d c

hig

-ge

rs,

bu

t, i

f d

ogs

are

aff

ecte

d w

ith

sca

bie

s, c

ats

may

no

t h

ave

to b

e tr

eate

d a

nd

vic

e v

ersa

(T

able

3-7

)

Tab

le 3

-7Se

lect

ed E

cto

par

asit

icid

al A

gen

ts in

Sm

all A

nim

al D

erm

ato

log

y

DR

UG

FORM

ULA

TIO

NC

OM

MEN

TS

IND

ICA

TIO

NS

SID

EEFF

EC

TS

DO

GD

OSE

(D)

CA

TD

OSE

(C)

Iver

mec

tin

Hea

rtw

orm

pre

vent

ion.

Ora

l and

subc

utan

eous

adm

inist

ratio

n: C

anin

ean

d fe

line

scab

ies,

Oto

dect

es c

ynot

isin

fest

a-tio

ns, d

emod

icos

is,ch

eyle

tiello

sis, l

ice

Topi

cal a

dmin

istra

tion:

Can

ine

scab

ies

Leth

argy

, ata

xia,

trem

ors,

myd

rias

is,

com

a, re

spir

ator

y ar

rest

Hea

rtw

orm

pre

vent

ion

at 6

mg/

kg m

onth

ly. O

ral

and

subc

utan

eous

adm

inist

ratio

n (w

ithgr

adua

l inc

reas

e fro

m 5

0to

300

mw

ithin

4 d

ays)

: 30

0 m

g/kg

dai

ly fo

rde

mod

icos

is un

til 8

wee

ks a

fter t

he fi

rst n

eg-

ativ

e sk

in sc

rapi

ng, f

our

adm

inist

ratio

ns 1

wee

kap

art f

or a

ll ot

her

ecto

para

sites

. (D

, C)

Topi

cal a

dmin

istra

tion:

Iver

mec

tin p

our-

on fo

rca

ttle

adm

inist

ered

at

500

mg/

kg (

0.1

ml/k

g)ap

plie

d al

ong

the

dors

alm

idlin

e tw

ice

2 w

eeks

apar

t was

repo

rted

to b

eef

fect

ive

for c

anin

e sc

abie

s.

10 m

g/kg

bov

ine

inje

ctab

le s

olut

ion

(oft

en g

iven

ora

lly t

osm

all a

nim

als)

, 10

mg/

ml e

quin

e or

also

luti

on

Idio

sync

rati

c to

xici

ties

mos

t co

mm

on in

Col

lies

and

Old

Engl

ish

Shee

pdog

s,bu

t al

so p

ossi

ble

inot

her

bree

ds. G

radu

aldo

se in

crea

se

from

50 m

g/kg

on

day

1 to

100

mg

on d

ay 2

,15

0 m

g on

day

3, 2

00m

g on

day

4 a

nd 3

00m

g on

day

5 t

o id

enti

fyse

nsit

ive

pati

ents

befo

re s

ever

e ad

vers

eef

fect

s oc

cur.

134

Tab

le 3

-7 c

on

tin

ued

DR

UG

FORM

ULA

TIO

NC

OM

MEN

TS

IND

ICA

TIO

NS

SID

EEFF

EC

TS

DO

GD

OSE

(D)

CA

TD

OSE

(C)

Milb

emyc

inox

ime

Lufe

nuro

n

Am

itra

z

Lym

e su

lfur

Hea

rtw

orm

pre

vent

ion,

scab

ies,

dem

odic

osis

Flea

infe

stat

ion

Can

ine

dem

odic

osis,

chey

letie

llosis

, sca

bies

and

Oto

dect

es c

ynot

isin

fest

atio

n

Ver

y sa

fe d

rug

Ver

y sa

fe d

rug

Seda

tion

, pru

ritu

s,hy

poth

erm

ia, h

yper

-gl

ycem

ia, h

ypot

ensi

on

Hea

rtw

orm

pre

vent

ion:

1

mg/

kg m

onth

ly. S

cabi

es:

2 m

g/kg

twic

e w

eekl

y fo

r 4

wee

ks. D

emod

icos

is: 2

mg/

kg d

aily

unt

il 8

wee

ksaf

ter t

he fi

rst n

egat

ive

skin

scra

ping

for d

emod

-ic

osis.

(D

, C)

10-1

5 m

g/kg

onc

em

onth

ly o

rally

wit

h fo

od (

D, C

) or

inje

ctab

leev

ery

6 m

onth

s (C

).

Mix

10.

6 m

l in

2 ga

l of

wat

er (

D)

and

rins

e q

7-14

day

s. C

onti

nue

for 8

wee

ks (

D)

afte

r the

firs

t-ne

gati

ve sc

rapi

ng.

2.3

mg,

5.7

5 m

g,

11.5

mg

and

23 m

gta

blet

s

45 m

g, 9

0 m

g,

204.

9 m

g, 4

09.8

mg

tabl

ets

(dog

s), 1

35 m

g,

270

mg

susp

ensi

on(c

ats)

.

10.6

ml,

50 m

l co

ncen

trat

e

Fair

ly c

ostl

y

All

hous

ehol

d an

imal

sne

ed t

o be

on

lufe

nuro

n fo

r ef

fect

ive

trea

tmen

t. B

reak

s lif

ecy

cle,

no

sign

ifica

ntad

ulti

cida

l act

ivit

y.

Ani

mal

mus

t no

t ge

tw

et in

bet

wee

n ri

nses

.A

nim

als

shou

ld n

ot

be r

inse

d w

hen

wet

.A

sthm

atic

peo

ple

shou

ld n

ot p

erfo

rm

the

rins

e.

97.8

% s

ulfu

rate

d lim

eso

luti

onSa

fe fo

r ev

en p

uppi

esan

d ki

tten

sC

heyl

etie

llosi

s, s

ca-

bies

, Oto

dect

es c

ynot

isin

fest

atio

n. F

elin

ede

mod

icos

is

Ver

y sa

fe d

rug

Dilu

te 1

par

t to

32

part

s w

ater

, app

ly a

sri

nse

or d

ip w

eekl

y fo

r4

wee

ks (

D, C

)

135

Sela

mec

tin

Imid

aclo

prid

Pyre

thri

n

Perm

ethr

in

Flea

-bit

e hy

pers

ensi

tiv-

ity,

Oto

dect

es c

ynot

isin

fest

atio

n, s

cabi

es,

hear

twor

m p

reve

ntio

n,ro

undw

orm

, and

hoo

k-w

orm

infe

stat

ions

Flea

-bit

e hy

pers

ensi

-ti

vity

Flea

-bit

e hy

pers

ensi

-ti

vity

Can

ine

flea-

bite

hype

rsen

siti

vity

Foca

l alo

peci

a(r

ever

sibl

e)

Foca

l alo

peci

a

Ptya

lism

, tre

mor

s,at

axia

, vom

itin

g,de

pres

sion

, hyp

erae

s-th

esia

, sei

zure

s,

dysp

nea

Ptya

lism

, tre

mor

s,at

axia

, vom

itin

g,de

pres

sion

, hyp

erae

s-th

esia

, sei

zure

s,

dysp

nea

6-12

mg/

kg m

onth

ly a

sa

spot

-on.

(D

, C)

0.4

ml (

C)<

4 k

g,

0.8

ml (

C)

> 4

kg.

0.4

ml (

D)

> 5

kg,

1

ml (

D)

5-10

kg,

2.

5 m

l (D

) 10

– 2

5 kg

, 4

ml (

D)

> 2

5 kg

Use

q 2

4-72

h (

D, C

)

Use

q 3

-10

days

(D

)

15 m

g, 3

0 m

g, 4

5 m

g,60

mg,

120

mg,

and

240

mg

tube

s.

9.1%

sol

utio

n (0

.4 m

l,0.

8 m

l, 1

ml,

2.5

ml,

4 m

l tub

es)

Spra

ys a

nd p

owde

rs a

t0.

05-0

.2%

Spra

ys, s

pot-

ons

and

sham

poos

at

0.2-

2%

Cos

met

ical

ly a

ppea

ling,

disp

erse

s qu

ickl

y. T

ooea

rly

to c

omm

ent

fur-

ther

at

tim

e of

wri

ting

Freq

uent

sha

mpo

oth

erap

y or

wat

er e

xpo-

sure

will

sig

nific

antl

yde

crea

se e

ffica

cy.

Solv

ent

may

dis

colo

rla

cque

r on

furn

itur

e.

Rep

elle

nt a

s w

ell a

sad

ulti

cide

. Low

tox

ici-

ty p

oten

tial

, sal

ivat

ion

in c

ats

Rep

elle

nt a

s w

ell a

sad

ulti

cide

. Low

tox

icit

yin

dog

s. N

ot t

o be

use

din

cat

s!

Fipr

onil

Flea

-bite

hyp

erse

nsiti

vi-

ty, t

icks

, pos

sibly

scab

ies

and

chey

letie

llosis

Tem

pora

ry ir

rita

tion

at si

te o

f app

licat

ion,

rare

hyp

erse

nsit

ivit

ies.

Con

trai

ndic

ated

inra

bbit

s

Spra

y: 4

-6 m

l/kg

q 2-

12w

eeks

(8-

12 p

umps

usi

ngth

e 10

0 m

l bot

tle,

2-4

pum

ps u

sing

the

250-

ml

bott

le).

(D

, C)

Spot

-on:

App

ly o

nce

mon

thly

0.29

% s

pray

in 1

00 a

nd25

0 m

l bot

tles

, 9.7

%so

luti

on (

0.5

ml,

0.67

ml,

1.34

ml,

2.68

ml)

Spra

y m

ore

effe

ctiv

eth

an sp

ot-o

n fo

rmul

a-tio

n, b

ut st

rong

smel

lun

avoi

dabl

e du

ring

appl

icat

ion.

For

hig

hest

effic

acy,

anim

als m

ay b

esh

ampo

oed

48 h

ours

befo

re a

pplic

atio

n, b

utno

t any

soon

er; e

xpo-

sure

to w

ater

doe

s not

inte

rfere

with

effi

cacy

.

136

Insect Control Trials andIndividual Management of Patients with Flea-biteHypersensitivity

Flea control trials✓ Treatment recommendations will vary significantly with indi-vidual situations. Confirmed flea-bite hypersensitivity, suspectedflea-bite hypersensitivity, or pets that show no sign of discomfort,but have some fleas, are treated very differently.

✓ Reasonably safe and effective products are available (Table 3-7). As veterinarians, we are in the best position toadvise clients on a flea-control program tailored to their specificneeds that considers their personality and life style as well astheir pet's little peculiarities.

� A major reason for failure of flea control programs is ownercompliance. They are either unwilling, not educated properly,too careless, or simply not physically able to do what we askthem to do for whatever reason. Choosing the right protocol andeducating owners properly, taking the time and possibly usingnursing staff, brochures, and message boards will greatly increaseyour chance of success.

� With all topical products, the first application should beadministered in the clinic by the veterinarian or the veterinarytechnician/nurse to demonstrate the correct procedure to theowner.

✓ Another reason for failure may be resistance of the organismto the products used. Resistance will always develop to any prod-uct, the question is thus not if, but rather when. In essence, wespeed up evolution and create resistant fleas by putting pressureon the population when using products for flea control.However, there are ways to delay this development of resistance.The first possibility is to combine different flea products, as it ismuch less likely that an individual flea gets resistant to two drugsat the same time. This approach is called integrated flea controland is becoming more popular all over the world. The secondpossibility is to switch products quickly when signs of resistanceoccur and kill the resistant flea with another effective productbefore it has time to multiply in big numbers.

137

✓ Suspected flea-bite hypersensitivity: Aggressive flea control isneeded for 4 to 6 weeks. If there is no improvement, we mostlikely do not deal with flea-bite hypersensitivity. With signifi-cant improvement or remission, we established a diagnosis andneed to discuss long-term strategies with that particular owner. Insuch a trial, we usually recommend the frequent use of an adulti-cide in combination with an insect growth regulator in the envi-ronment to quickly lower the flea pressure (Tables 3-8 and 3-9).

✓ Confirmed flea-bite hypersensitivity: Ideally, we recommendan insect growth regulator/insect development inhibitor on apermanent basis (systemically, topically or in the environment)and an adulticide as needed (Tables 3-8 and 3-9). The secondoption is an adulticide only, in which case we need to switchproducts very quickly at the first sign of resistance. However, asadulticides are tapered slowly to identify the longest possibleinterval in between applications, recurrences may indicate insuf-ficient frequency of application rather than resistance.

✓ No flea-bite hypersensitivity present: In these cases, we donot recommend flea control because permanent flea exposuremay be less likely to induce flea-bite hypersensitivity than off-and-on flea control by an owner who is not pressed into compli-ance by an itchy pet. If the client does want to start some sort offlea control, insect growth regulators or development inhibitorsare recommended.

Mosquito-bite trialThe safest and most thorough mosquito-bite trial in cats withpapules and crusted papules on nose, pinnae or foot pads is tokeep the patient indoors for 2 weeks. When there is no expo-sure to mosquitoes, the disease regresses rapidly. However, incats used to outdoors this option may not be viable.Alternatively, exposure is decreased when outdoor activities arelimited and cats are trained to come in before dawn by feedingthem in the late afternoon. In addition, a mosquito repellentsafe for use in cats such as pyrethrin spray may be applied bywetting a cloth and wiping the feet and head daily before the cat goes out.

138

Tab

le 3

-8A

dm

inis

trat

ion

, A

dva

nta

ges

, an

d D

isad

van

tag

es o

f Se

lect

ed F

lea

Co

ntr

ol P

rod

uct

s

DR

UG

AD

MIN

ISTR

ATI

ON

AD

VA

NTA

GES

DIS

AD

VA

NTA

GES

CO

MM

EN

TS

Feno

xyca

rbC

ompa

rati

vely

saf

e an

def

fect

ive,

rap

id o

nset

of

acti

on

Wor

k-in

tens

ive

Fogg

ers

are

mor

e co

nven

ient

but

do

not

cove

r m

ore

than

2 r

oom

s/ca

n. T

he in

sect

i-ci

de s

tays

on

shel

ves

and

furn

itur

e, b

ut a

reas

unde

rnea

th fu

rnit

ure

are

not

cove

red!

Spra

ys a

re le

ss c

onve

nien

t an

d m

ore

wor

k-in

tens

ive,

but

inse

ctic

ide

is d

epos

ited

onl

yw

here

nee

ded.

Use

in a

ll ro

oms

wit

h pe

tac

cess

! C

arpe

ted

area

s, c

revi

ces,

and

cor

ners

as w

ell a

s ar

eas

unde

rnea

th fu

rnit

ure

are

mos

t im

port

ant.

Ind

icat

ed w

ith

freq

uent

vis

-it

ing

anim

als

not

on fl

ea c

ontr

ol a

s w

ell a

sat

the

sta

rt o

f an

inse

ct-c

ontr

ol t

rial

.

Expe

nsiv

e in

mul

ti-p

etho

useh

olds

, lag

per

iod

ofse

vera

l wee

ks t

o m

onth

s.

Wor

k-in

tens

ive

Fogg

ers

are

mor

e co

nven

ient

, but

do

not

cove

r m

ore

than

2 r

oom

s/ca

n. T

he in

sect

i-ci

de s

tays

on

shel

ves

and

furn

itur

e, b

ut a

reas

unde

rnea

th fu

rnit

ure

are

not

cove

red!

Spra

ys a

re le

ss c

onve

nien

t an

d m

ore

wor

k-in

tens

ive,

but

inse

ctic

ide

is d

epos

ited

onl

yw

here

nee

ded.

Use

in a

ll ro

oms

wit

h pe

tac

cess

! C

arpe

ted

area

s, c

revi

ces,

and

cor

-ne

rs, a

s w

ell a

s ar

eas

unde

rnea

th fu

rnit

ure

mos

t im

port

ant.

Ind

icat

ed w

ith

freq

uent

vis

-it

ing

anim

als

not

on fl

ea c

ontr

ol a

s w

ell a

sat

the

sta

rt o

f an

inse

ct c

ontr

ol t

rial

.

Indi

cate

d in

hou

se-h

olds

wit

h fe

w p

ets

and

no v

isit

s fr

om a

nim

als

wit

hout

tho

roug

h fle

aco

ntro

l.

Lufe

nuro

n

Met

hopr

ene

or Pyri

prox

ifen

Indo

ors:

spra

y q

12 m

.O

utdo

ors:

Spot

tre

at-

men

t of

alle

rgic

pet

'sfa

vori

te s

pots

q 6

-12

m

in d

ry e

nvir

onm

ents

.

10-1

5 m

g/kg

q 3

0 d

oral

ly(D

), 2

5-50

mg/

kg S

C

q 6

m (

C).

Indo

or s

pray

q 6

mC

ompa

rati

vely

saf

e an

def

fect

ive,

rap

id o

nset

of

acti

on.

Con

veni

ent,

safe

st e

nvir

onm

enta

lly

Inse

ct g

row

th r

egu

lato

rs/d

evel

op

men

t in

hib

ito

rs

139

No

repe

lling

act

ion,

expe

nsiv

e in

larg

e an

i-m

als,

via

ble

egg

prod

uc-

tion

pos

sibl

e.

Not

wat

er p

roof

, no

repe

lling

viab

le e

gg

prod

ucti

on p

ossi

ble.

Flea

nee

ds t

o bi

te

anim

al t

o di

e, o

nly

effe

ctiv

e fo

r le

ss t

han

one

day

Wor

k-in

tens

ive,

rare

but

pos

sibl

e to

xici

-ti

es, d

epen

ding

on

prod

-uc

t an

d pa

tien

t; da

ily-t

o-m

onth

ly a

pplic

atio

n

Sham

poo

only

2 d

ays

befo

re n

ew a

pplic

a-ti

on. S

wim

min

g or

roa

min

g in

rai

ny w

eath

erno

t re

com

men

ded.

May

be

give

n da

ily w

ith

no a

dver

se e

ffect

s.Pa

rtic

ular

ly u

sefu

l for

pro

phyl

acti

c ad

min

is-

trat

ion

in a

nim

als

on lu

fenu

ron

dire

ctly

befo

re a

ntic

ipat

ed e

xpos

ure

in s

how

s or

vis

its.

Soak

ani

mal

with

spra

ys (

pres

sure

pum

p sp

rays

may

be

usef

ul fo

r big

ger o

r lon

g-ha

ired

dogs

).

Spra

y ne

eds

to b

e ap

plie

d ca

refu

lly, c

over

ing

the

anim

al's

who

le b

ody.

Spo

t-on

form

ula-

tion

eas

ier

to a

pply

, but

less

effe

ctiv

e.A

dmin

iste

r ou

tdoo

rs o

r in

wel

l-ve

ntila

ted

area

due

to

stro

ng s

mel

l dur

ing

first

min

utes

.Sh

ampo

o on

ly 2

day

s be

fore

new

app

licat

ion.

Fipr

onil

Imid

aclo

prid

Nit

enpy

ram

Pyre

thri

n

0.29

g/1

00 m

l, 10

-15

mg/

kg a

s a

spra

y di

stri

b-ut

ed o

ver

the

who

lebo

dy q

2-8

wee

k, s

pot-

on

q 2-

8 w

eek

100

mg/

ml

Tabl

ets

q 1-

2 d

or a

sne

eded

Con

veni

ent,

beca

use

used

onl

y ev

ery

2-4

wee

ks, e

asy

to a

pply

Con

veni

ent,

rapi

d on

set

of a

ctio

n, s

afe

Rep

els

inse

cts,

quic

kkn

ock-

out

Wat

er-p

roof

(bu

t no

tsh

ampo

o pr

oof!

),co

nven

ient

, bec

ause

use

don

ly e

very

2-4

wee

ks

Ad

ult

icid

es

140

Tab

le 3

-8 c

on

tin

ued

DR

UG

AD

MIN

ISTR

ATI

ON

AD

VA

NTA

GES

DIS

AD

VA

NTA

GES

CO

MM

EN

TS

Perm

ethr

inR

epel

ling

acti

on, q

uick

knoc

k-ou

t.W

ork-

inte

nsiv

e,ra

re b

ut p

ossi

ble

toxi

ci-

ties

, dep

endi

ng o

n pr

od-

uct

and

pati

ent;

dai

ly-t

o-m

onth

ly a

pplic

atio

n

Soak

ani

mal

wit

h sp

rays

(pr

essu

re p

ump

spra

ys m

ay b

e us

eful

for

bigg

er o

r lo

ng-

hair

ed d

ogs)

.

Too

new

to

com

men

t at

tim

e of

wri

ting

Too

new

to

com

men

t at

tim

e of

wri

ting

.Se

lam

ectin

744

mg

in 1

ml a

s a

spot

-on

for

dogs

<15

kg,

148

8m

g in

2 m

l for

dog

s >

15kg

. Do

not

use

in c

ats.

6-12

mg/

kg m

onth

ly a

s a

spot

-on

Easy

to

use,

cos

met

ical

lyap

peal

ing,

saf

e

Tab

le 3

-9A

pp

licat

ion

of

Sele

cted

Fle

a Pr

od

uct

s in

Pat

ien

ts w

ith

Co

nfi

rmed

ver

sus

Susp

ecte

d F

lea-

bit

e H

yper

sen

siti

vity

DR

UG

CO

NFI

RM

ED

FLE

A-B

ITE

HY

PER

SEN

SIT

IVIT

Y*

SU

SPEC

TED

FLE

A-B

ITE

HY

PER

SEN

SIT

IVIT

Y

Fipr

onil

spot

-on

Fipr

onil

spra

y

Imid

aclo

prid

spo

t-on

Nit

enpy

ram

Perm

ethr

in s

pot-

on

Perm

ethr

in s

pray

Pyre

thri

n sp

ray

Sela

mec

tin

* In

any

flea

con

trol

tri

al a

dult

icid

es a

re c

ombi

ned

wit

h an

inse

ct g

row

th r

egul

ator

use

d in

the

env

iron

men

t at

the

beg

inni

ngof

the

tri

al.

q 2-

4 w

eeks

Not

use

d fo

r in

sect

con

trol

tri

als

q 4

-12

wee

ksq

7-14

d fo

r 4-

6 w

eeks

*

q 4

wee

ks

In a

ddit

ion

to lu

fenu

ron,

whe

n pa

tien

t sh

ows

clin

i-ca

l sig

ns o

r be

fore

sus

pect

ed e

xpos

ure

q 4

wee

ks

Var

ying

dep

endi

ng o

n in

divi

dual

pro

duct

up

to

q 7-

14 d

Var

ying

dep

endi

ng o

n in

divi

dual

pro

duct

up

to

q 7-

14 d

q 4

wee

k

q 7-

14 d

for

4-6

wee

ks*

q 1-

2 d

for

4-6

wee

ks*

Not

use

d fo

r ins

ect c

ontr

ol tr

ials

Var

ying

dep

endi

ng o

n in

divi

dual

pro

duct

up

to q

2-3

d fo

r 4-

6 w

eeks

*V

aryi

ng d

epen

ding

on

indi

vidu

al p

rodu

ct u

p to

q2-

3 d

for

4-6

wee

ks*

q 14

d fo

r 4-6

wee

ls*

141

ImmunosuppressiveTherapy

� Before you think about immunosuppressive therapy you mustbe sure about your diagnosis. It can be very dangerous for yourpatient to start immunosuppressive drugs based only on historyand clinical examination as a confirmation of the diagnosis ofimmune-mediated skin disease. If the animal has an infectiousdisease (fungal, bacterial, or parasitic), it can rapidly deteriorateand even die. There is no place for trial therapy in immune-mediated disease (except in the case of a patient facingeuthanasia otherwise).

� Patients with immune-mediated skin disease commonly havesecondary infections that need to be identified and treated. Inpatients with mild-to-moderate disease, I start antimicrobialtherapy 3 weeks before immunosuppressive therapy to evaluatehow many of the clinical signs are due to the infection and howmany are due to the immune-mediated disease. In cases of severeclinical disease, however, treatment of infection and of theimmune-mediated disease should be started concurrently.

� It is impossible to give you a good general purpose recipefor immunosuppression. Every dog or cat reacts differently toeach of the drugs mentioned later in this section and you haveto individualize treatment for each patient. Immunosuppressionis a technique requiring instinct, sensitivity, and experience aswell as theoretic knowledge that is beyond the scope of this text.There are, however, certain generalizations as well as certainstarting dosages and ranges.

✓ Probably the best way is to start using one preferred drug,then, if your approach fails, refer the patient and learn from theway the specialist treats it. After you are familiar with that newdrug, you add another one to your repertoire and use both ofthem and so on.

✓ The doses mentioned in Table 3-10 are starting doses that aretapered as soon as possible to the smallest effective dose.

142

✓ Taper the drug once the patient is in clinical remission or ifadverse effects are intolerable. In a patient with severe adverseeffects and concurrent clinical signs of active disease, new drugsneed to be added at the same time.

� Monitoring, as described in Table 3-10, is essential. I onlycompromise on monitoring standards because of financial con-siderations in patients facing euthanasia otherwise!

✓ Some dogs will have seasonal relapses. This mechanism iscurrently not understood. If a well-controlled patient suddenlyseems to relapse, always check for demodicosis and fungal or bac-terial infections first. Rather than a flare-up of the immune-medi-ated disease you may be encountering a problem secondary toyour treatment. These patients are immunosuppressed and thuseasily may be affected by infectious diseases! Increasing the doseof the immunosuppressive drug may not always be a good idea.

143

Tab

le 3

-10

Dru

gs

Use

d in

Im

mu

no

sup

pre

ssiv

e Th

erap

y

DR

UG

FORM

ULA

TIO

NC

OM

MEN

TS

AD

VER

SE

EFF

EC

TS

DO

SE

MO

NIT

OR

ING

Pred

niso

ne/

Pred

niso

lone

Rap

id o

nset

of a

ctio

n,in

expe

nsiv

e, r

espo

nse

rate

app

roxi

mat

ely

50%

,hi

gh r

ate

of a

dver

seef

fect

s

Poly

uria

, pol

ydip

sia,

poly

phag

ia, l

etha

rgy,

infe

ctio

ns, m

uscl

e w

asti

ng,

pant

ing,

exe

rcis

e in

tole

r-an

ce, c

alci

nosi

s cut

is

1-2

mg/

kg q

12

h (D

),3-

4 m

g/kg

q 1

2 h

(C)

Vom

iting

, dia

rrhe

a (l

ess

com

mon

, if a

dmin

ister

eddi

vide

d in

to 2

dai

ly d

oses

),bo

ne m

arro

w su

ppre

ssio

n,id

iosy

ncra

tic h

epat

otox

ici-

ty (

poss

ibly

per

acut

e)

2 m

g/kg

or

50 m

g/m

2 q

24 h

(D

)

Uri

naly

sis

and

urin

e cu

ltur

es

q 6

mo,

pos

sibl

ybi

oche

mis

try

pan-

els

and

AC

TH

stim

ulat

ion

test

s q

6-12

mo

Com

plet

e bl

ood

coun

ts a

t 0,

1, 2

,4,

8, 1

2 w

k an

dth

en e

very

3-6

mo,

pos

sibl

y se

rum

bioc

hem

istr

y co

n-cu

rren

tly,

par

ticu

-la

rly

duri

ng t

hefir

st 1

-2 m

o.

Aza

thio

prin

e*

5 m

g, 2

0 m

g, 2

5 m

g,

50 m

g ta

blet

s

25 m

g ta

blet

s,50

mg

tabl

ets

Lag

peri

od o

f sev

eral

wee

ks in

dog

s. Sh

ould

not

be u

sed

in c

ats!

!! F

urth

erre

adin

g is

rec

omm

ende

dbe

fore

usi

ng t

his

drug

.

Vom

itin

g, d

iarr

hea,

bone

mar

row

sup

pres

sion

.

Bon

e m

arro

w s

uppr

es-

sion

, occ

asio

nal c

uta-

neou

s er

upti

ons

and

prot

einu

ria

0.1-

0.2

mg/

kg q

24

h(D

, C)

1 m

g/kg

q 7

d IM

(D

,C)

afte

r a te

st d

ose

of

1 m

g/an

imal

. Tap

erin

g to

q

2 w

k, 3

wk,

4 w

k af

ter

rem

issio

n ac

hiev

ed

Com

plet

e bl

ood

coun

ts a

t 0,

1, 2

,4,

8, 1

2 w

k an

dth

en e

very

3-6

mo

Com

plet

e bl

ood

coun

ts a

nd u

rinal

y-sis

at 0

, 1, 2

, 4, 8

,12

wk

and

then

ever

y 3-

6 m

o.Se

rum

bio

chem

-is

try

mon

thly

ini-

tial

ly, t

hen

ever

y3-

6 m

o.

Chl

oram

buci

l*

Aur

othi

oglu

cose

*

Long

lag

peri

od (

4-8

wk)

.Sa

fest

imm

unos

uppr

essi

veag

ent,

may

be

used

inca

ts. F

urth

er re

adin

g is

reco

mm

ende

d be

fore

usin

g th

is d

rug.

Long

lag

perio

d (6

-12

wk)

. May

be

used

in c

ats.

Som

e an

imal

s go

into

com

plet

e re

miss

ion

and

cess

atio

n of

ther

apy

may

be p

ossib

le. F

urth

er re

ad-

ing

is re

com

men

ded

befo

re u

sing

this

drug

.

2 m

g, 5

mg

tabl

ets

50 m

g/m

l sus

pens

ion

DO

GD

OSE

(D)

CA

TD

OSE

(C)

144

Tab

le 3

-11

Sele

cted

Dru

gs

Use

d in

th

e Tr

eatm

ent

of

End

ocr

ine

Dis

ord

ers

wit

h C

uta

neo

us

Sym

pto

ms

DR

UG

DO

SE

IND

ICA

TIO

NS

AD

VER

SE

EFF

EC

TS

o,p´

-DD

D*

(mit

otan

e)Id

iopa

thic

hyp

erad

reno

cort

icis

m,

adre

nal s

ex h

orm

one

imba

lanc

e (I

do n

ot r

ecom

men

d th

e dr

ug fo

rth

is la

tter

dis

ease

). F

urth

er r

ead-

ing

is r

ecom

men

ded

prio

r to

usi

ngth

is d

rug.

Leth

argy

, ata

xia,

vom

itin

g, d

iarr

hea,

anor

exia

.

Poly

dips

ia, p

olyu

ria,

ner

vous

ness

,ag

gres

sive

ness

, pan

ting

, dia

rrhe

a,ta

chyc

ardi

a, p

yrex

ia, p

ruri

tus,

hea

rtfa

ilure

in d

ogs

wit

h ca

rdia

c di

seas

e,ex

acer

bati

on o

f adr

enal

cri

sis

in d

ogs

wit

h hy

poad

reno

cort

icis

m

Agg

ress

ive

beha

vior

, gre

asy

hair

coat

,pr

osta

tic

hype

rtro

phy,

hep

atot

oxic

ity

Estr

us in

duct

ion,

bon

e m

arro

w s

up-

pres

sion

, hep

atot

oxic

ity,

pyo

met

ra,

spon

tane

ous

abor

tion

Levo

thyr

oxin

e

Test

oste

rone

Estr

ogen

Hyp

othy

roid

ism

Estr

ogen

-res

pons

ive

derm

atos

is

25 m

g/kg

q 1

2 h

durin

g in

duct

ion

(5-1

4 d)

, sam

e do

se q

12

h on

2 c

on-

secu

tive

days

of e

ach

wee

k as

mai

n-te

nanc

e. L

engt

h of

indu

ctio

n de

ter-

min

ed b

y w

ater

inta

ke, f

ood

inta

ke,

and

AC

TH

stim

ulat

ion

test

. (D

, C)

20 m

g/kg

q 1

2 h.

If p

atie

nt c

ondi

-ti

on is

wel

l con

trol

led,

med

icat

ion

may

be

chan

ged

to o

nce

daily

at

doub

le d

ose.

(D

, C)

0.5-

1 m

g/kg

(up

to

a m

axim

al d

ose

of 3

0 m

g) q

24

h or

ally

(D

, C)

0.02

mg/

kg q

48

h fo

r 6-

12 w

k or

al-

ly o

r q

24 h

for

3 w

k, t

hen

1 w

k of

f,th

en r

epea

t cy

cle

(D).

Mel

aton

inC

yclic

folli

cula

r dy

spla

sia,

folli

cu-

lar

dysp

lasi

a, a

lope

cia.

Abs

cess

form

atio

n w

ith

inje

ctio

n of

repo

sito

ry c

apsu

les.

Ana

phyl

axis

, acr

omeg

aly,

dia

bete

sm

ellit

usG

row

th h

orm

one*

Adr

enal

sex

horm

one

imba

lanc

e,gr

owth

-hor

mon

e re

spon

sive

dis-

ease

(I d

o no

t rec

omm

end

trea

t-m

ent w

ith th

is dr

ug).

3-6

mg

q 12

-24

h fo

r 2-

3 m

o (D

)

0.1

IU/k

g q

56 h

for

6 w

k (D

)

Treatm

ent

of

Alo

peci

a d

ue t

o H

orm

onal

Dis

ease

s and

Folli

cula

r D

ysp

lasi

a (

Tab

le 3

-11)

DO

GD

OSE

(D)

CA

TD

OSE

(C)