1 introduction to dermatology. 2 dermatology deals with disorders of skin, hair, nails, and mucous...

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INTRODUCTION TO

DERMATOLOGY

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Dermatology deals with disorders of skin, hair, nails, and mucous membranes.

Important functions of the skin

Protection against external injuryFluid balanceTemperature organSynthesis of Vit DPart of immune system (e.g. langerhan’s cell)Cosmetic function.

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•Dermatological disorder = 10% -15% of primary care consultations

•Skin is the largest organ in human body

•Dermatological diseases can cause social and psychological problems, also it may affect ability to work (e.g.. Chronic hand dermatitis.)

•Skin is the gate of the body(might reflect systemic disease).

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Structure of skin1 Epidermis2 Basement membrane (dermoepidermal junction)3 Dermis4 Subcutaneous fat

Epidermis: Four layers (from outside – inside)1. Cornified layer2. Granular layer3. Spinous layer4. Basal layer

Dermis contains:Collagen fibersElastic fibersGround substancesBlood vesselsNerves.

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Skin appendages:

Hair follicle

Sebaceous gland

Arrector pili muscle

Eccrine sweat gland

Apocrine sweat glands

Nail

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Dermatological History age, sex

Chief complaint : + durationitchingburningpain

History of present illness

When and how started?

Mild, moderate or severe?

Aggravating or reliving factors?

Any other symptoms

Review of systemsPast medical history

Drug history

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OccupationHobbiesTravelFamily history

Examination: 3 corners to make useful skin exam 1. Morphology (shape of the lesion)2. Configuration (arrangement of lesions)3. Distribution (Which body site)Morphology:- 1º skin lesions : unmodified lesions - 2º skin lesion: modified by scratching or infection

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Primary Lesions Secondary lesionsMacule CrustPapule ErosionPlaque ScaleNodule UlcerationCyst ExcoriationWheal ScarVesicle AtrophyBulla FissurePurpura NecrosisBurrow LichenificationTelangectasia

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Primary skin lesions

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Macule & patch

• A macule is a circumscribed flat alteration in the colour of the skin which is less than 1 cm in diameter.

• Various colors depending on the cause

• A patch is a flat lesion greater than 1 cm in diameter (i.e. a large macule).

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Papule

• A papule is a circumscribed palpable elevation of the skin less than 1 cm in diameter

• Dermal(drug eruption, lipid deposits), epidermal (warts, molluscum), or both (lichen planus)

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Nodule

Palpable solid deep lesion (depth> diameter)

- Epidermal

- Dermal

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Plaque

• A slightly raised lesion greater than 1 cm in diameter

• Papules confluence (psoriasis)

• Patch thickening (mycosis fungoides)

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Vesicle

• A raised lesion less than 0.5 cm in diameter containing clear fluid

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Bulla

• A vesicle that is greater than 0.5 cm in diameter is known as a bulla.

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Pustule

• A pustule is a raised lesion less than 0.5 cm in diameter containing yellow fluid, which may be sterile as in acne or pustular psoriasis, or infected.

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Wheal

• A wheal is a transient, itchy, pink or red swelling of the skin, often with central pallor.

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Cyst:

palpable soft sac containing fluid.

- Epidermal

- Dermal

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Telangiectasia

• Dilatation of capillaries gives rise to this skin condition.

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Secondary skin lesions

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Crust

• A crust is a dried exudate, which may have been serous, purulent or haemorrhagic.

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Excoriation

• A haemorrhagic excavation of the skin resulting from scratching.

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Lichenification

• Thickening of the skin with exaggeration of the skin creases.

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Scar

• The final stage of healing of a destructive process (disease or injury) that has involved the deeper dermis results in a white, smooth, firm, shiny lesion.

• Atrophic, or hypertrophic

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Scale

• A scale is a flat plate (lamella) or flake of stratum corneum.

• The epidermis is replaced every 28 days• Fine (eczema) / thick (psoriasis) • No scaling in dermal pathologies

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Poikiloderma

• This refers to an appearance of pigmentation, atrophy and telangiectasia

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Necrosis

• Death, or necrosis, of skin tissue is usually black in colour.

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Erosion

• A partial break in the epidermis is known as an erosion

• It heals without scarring unless secondary infection occurs.

• Commonly following a blister

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Ulcer

• An ulcer is a full-thickness loss of the epidermis

• Heals with scarring

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FISSURE

a linear cleavages or cracks in the skin.

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Atrophy

• Thinning and transparency of the skin

• Caused by diminution of the epidermis, the dermis, or both

• Wrinkling and translucency

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Sclerosis

• A circumscribed or diffuse hardening or induration of the skin

• A result of dermal or subcutaneous edema, cellular infiltration, or collagen proliferation

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Primary Lesions

•Macule: Flat circumscribed area of change in skin color•Papule: small circumscribed elevation of the skin•Nodule:Solid, circumscribed elevation of the skin whose greater part is beneath skin surface (felt more than seen)•Plaque: flat topped palpable lesion (gathering of papules)•Vesicle: collection of clear fluid (<5mm in diameter)•Bulla: like vesicle, but > 5 mm•Pustule: Collection of Pus

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Primary Lesions

* Wheal: Transient, slightly raised lesion with pale center and pink margin.Seen in urticaria.

* Purpura:Visible collection of blood under the skin e.g. Vasculitis

* Telangectasia: Dilated capillaries visible on skin surface

* Burrow: Tunnel in the skin (e.g. Scabies)

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Secondary lesions•Crust: Dried serum (or exudate)•Scale:Thickened, loose, readily detached fragment of cornified layer•Excoration: Shallow linear abrasion caused by scratching.• Erosion:Loss of epidermis (heals without scarring)•Ulcer: loss of epidermis and dermis (heals with scarring)• Fissure : linear crack in the skin•Scar: Permanent lesion due to abnormal formation of connective tissue following injury.

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Secondary lesions

Atrophy: A-Superficial: thining of skin with visible blood vessels

B-Deep : depression of skin surface

Lichenification: thickened skin with

accentuated skin markings

Sclerosis: induration of skin

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Distribution

Predilection for specific body sites*Psoriasis: Extensors(elbows and knees)

Scalp*Acne:Face

Upper chest, Upper back*Photosensitive eruption: Mainly face, forearms & V-Chest (with sparing of photoprotected areas e.g. upper eyelids, retro-auricular an sub- mental)

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Colour in Dermatology

Red:Vascular lesions e.g. port wine stain

also, inflammatory disorders like psoriasisBlue: Blue nevus

Mongolian spotYellow: XanthomaWhite: VitiligoBlack: Melanocytic nevus & melanomaPurple or (Violaceous) : Lichen planus

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Some important signs in Dermatology

*Auspitz sign: When you remove a scale from psoriasis lesion tiny bleeding points (due to suprapapillary thinning).

Nikolsky sign: When you rub normal skin beside blister induction of new blister .Seen in pemphigus vulgaris and toxic epidermal necrolysis(TEN).

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Nikolsky sign

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Dermatographism: When you stroke the normal skin edema and erythema (you can write on skin!) .Seen in physical urticaria

Kobener Phenomenon: Induction of new skin lesions on previously normal appearing skin by truma e.g. in psoriasis, wart, lichen planus

Button-hole sign: In neurofirbroma, if you try to push it it goes inside the skin

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Additional skin examination:~Wood’s Lamp: Produces long wave ultraviolet light(UVA). e.g. Vitiligo milky whiteTinea Versicolor goldenTinea Capitis (caused by microsporum) yellow greenErytherasma coral red

~Diascopy:you press with a glass slide .If there is red lesion and the redness dose not go away by this pressure this means extravasated blood i.e.purpura

~Dermatoscopy: Helpful to differentiate benign from malignant pigmented lesions.

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Investigations:*KOH and fungal culture•Scrap skin scales put over glass slide•Add KOH 10% -- warm gently•See under microscope•You may see hyphae and/ or spores

*Gram stain and bacterial culture

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Investigations:Tzank smear: Scrap base of vesicle smear it on microscopic slide add fixative add Giemsa stain.Examine under microscope for 1.Detached epidermal cells (acantholytic cells) in pemphigus vulgaris2.Multinucleated giant cells in herpes simplex, zoster or varicella

Viral culture

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Skin biopsy : Under local anasthesia, different types: Punch

ShaveExcisionalIncisional

Immunofloursence : important in immunobullous disorder

1. Direct : use pt’s skin2. Indirect: use pt’s Serum

Prick test

Patch test

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Treatment:

Topical corticosteroids

Mechanism of action

1. Anti-inflammatory

2. Anti-proliferative

3. Vascoconstrive

4. Immunosuppressive

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Topical steroids (cont’d)7 Categories, according to strength .

Category one is superpotent (used only on chronic cases or resistant disorder on thick skin) .Not used on face or in children. e.g. Dermovate (clobetasol propianate).

Category seven is very mild: can be used safely in children or over face, also for longer periods of treatment

See tables.

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Group 1 (Most Potent)Clobetasol propionate ointment 0.05% (Temovate,Dermovate)Clobetasol propionate cream 0.05% (Temovate, Dermovate)Betamethasone dipropionate ointment 0.05% (Diprolene)Group 2Betamethasone dipropionate cream 0.05% (Diprolene)Mometasone furoate ointment 0.1% (Elocom)Group 3Fluticasone propionate 0.005% (Cutivate)Group 4Mometasone furoate cream 0.1% (Elocom)Triamcinolone acetonide ointment 0.1% (Kenalog)Hydrocortisone valerate cream 0.2% (Westcort)Hydrocortisone butyrate ointment 0.1%(Locoid)Group 5Fluticasone propionate cream 0.05% (Cutivate)Triamcinolone acetonide 0.1% (Kenalog)Hydrocortisone valerate cream 0.2% (Westcort)Hydrocortisone butyrate cream 0.1%(Locoid)Group 6Alclometasone dipropionate 0.05% ointment (Perderm)Alclometasone dipropionate 0.05% cream (Perderm)Group 7Topical preparations with hydrocortisone acetate 1%

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Topical steroids (cont’d)Various formulations:Ointment, cream ,gel, solution, lotion

Side effects (if used for long period and at inappropriate site):

Atrophy , AcneTelangectasia, Hypertrichosis

Folliculitis, Hypopigmentation

If large amounts systemic absorption .But if you use it with appropriate strenght and amount in appropriate site; these S/E are unlikely to happen

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•Topical Antifungal :

–Miconazole–Terbinafine–Clotrimazole–Ketoconazole etc….

•Topical Antibiotids:

–Fusidic acid–Mupirocin–Erytheromycin–Clindamycin etc…

•Topical retinoids (vit.A derivatives)

–Commonly used In Acne–e.g. Treitinoin(Retin A) Adapalene(Differin)

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*Topical vit. D analoguescalcipotriene (daivonex).Used in psoriasisMain S/E :hypercalcaemia if more than 90 grams used per week (for adult)

*Topical chemotherapy:e.g. 5 -flurouracial, used for actinic keratosis (premalignant skin lesions)

*Topical immunomodulator :e.g. -Imiquimod(Aldara )used for genital warts

*Topical immunosuppersives: e.g.-Tacrolimus used for Atopic Dermatitis

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Intralesional treatment

*IL steriods : e.g. Triamcenolone acetonide (kenalog) with different concentration according to the case

Used in many skin disease e.g.

Alopecia areata (localized vaiant)

Keloids

Licen simplex chronicus

Hemanigomas

S/E: atrophy

hypopigmentation.

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I L chemotherapy:

*Bleomycin : for plantar warts

*Vinerstine and vinblastine: for kaposi sarcoma

IL Antiprotoza:

like Na stibogluconate used in treatment of leishmaniasis

Intramuscular injections:

*Steriods

*Pentostam (Na stibogluconate)

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Physical methods

-Cryotherapy : e.g. Liquid Nitrogen used in treatment of warts

-Electrcautery

-Sclerotherapy for varicose viens

-Curettage

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Oral Medications

Systemic steroids:

The most commonly used is prednisoloneWhat are the S/E ? DM ,Wt gain

HTNHPA axis suppersionOsteoprosis,

Avascular necrosis Pyschosis,Depression etc….How to prevents them?

Monitor BP, blood sugarVit. D. ,Calcium supplement

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Oral Medications

Antibiotics:

PencillinsCephalosporinsMacrolides

FluoroquinolonesTetracyclinesAnti-TBAnti- Leprosy

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Oral Medications

• Antifungal : e.g.Terbinafine GriseolfulvinItraconazole Ketoconazole

• Antiviral

Acyclovir

Famcilovir

Valacyclovir

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Oral Medications

*Immunosuppressive and antiproliferativeAzathiopurine (imuran)Cyclosporin-AMycophenolate MofetilCyclophosamideMethotrexate

*Antimalaria* Interferones *Systemic Retinoids

e.g. Isotreitonoin, used in acne Acitertin used in psoriasis S/E?(elevate LFT and Lipids,also Teratogenic)

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Oral MedicationsAntihistamine:for itching

-sedating(e.g.Hydroxyzine,Chlorphenarmine)

-non sedating(e.g Loratidine and Cetrizine)

Antiandrogens

Psychotropic

Colchicine

Potassium iodide

Emoillents

Sunscreen: Chemical and physical

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Phototherapy

Ultraviolet light A or Bwith or without psoralen

PUVA (psoralen + UVA)New modalities:

Narrow band UVBUVA – 1

Excimer laser(308nm)Indications: psoriasis, vitiligo, atopic dermatitis,CTCL(cutaneous T cell lymphoma )etc…

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Laseracronym for:

LightAmplificationStimulatedEmissionRadiation

Harmful if accidently goes to the eye.Does not induce cancerSafe for pregnant ladiesDifferent wavelengths targeting different chromophoresTypes: Vascular , Pigmentary

Resurfacing, Hair removal

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Er C02 KTP PD Ruby Alex Nd YAG

Laser Tissue Interactions

Depth of Penetration

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Thank you