1- initial lesions

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Functions of skin:1. Protection2. Temperature regulation3. Sensation4. Excretion

5. Synthesis of vitamin D6. Absorption7. Psychogenic function

For diagnosis of a dermatologicaldisease, certain items must befulfilled;

1- History taking.2- Clinical examination.

3- Investigations (if needed).

A) History

1-Personal History:A) Name: for patient identification.

B) Age & sex: certain diseasesoccur in certain age and sex. (acne& C.T)C) Occupation:skin exposed toexternal environment. (house wives)D) Residence: endemic disorder suchas leprosy.

2-Present History:A)Complaint: may be disfigurement,itching or burning sensation.B)Onset: acute, chronic or acuteexacerbation on top of chronicillness.C)Course: progressive, stationaryor regressive.

3-Past History:Important in recurrent disorders.

4-Family History:Important in congenital andinfestation disorders.

5-Drug History:Drugs taken before appearance ofthe disease.

B) Clinical Examination

1- General examination:Skin disorders associated with

systemic disorders.2- Local examination:I) Examination of skin:

1- Examination from distance.2- Close-up examination.II) Examination of skin appendages:Mucus membrane, nails and hair.

Examination of the skin:

A) From distance:Shows the distribution of

lesions that may be:1) Discrete distribution:Multiple lesions separatedby normal skin.2) Unilateral distribution:Lesions involving only oneside of the body.

3) Generalized distribution:Lesions involving more than50% of body surface area.

4) Grouped distribution:Lesions are restricted toa localized area.

5) Linear distribution:Lesions are arranged a long

a line. It may be Kobner`sphenomenon which isappearance of isomorphic

lesions along the site ofblunt trauma.6) Zosteriform distribution:Lesions are restricted tocertain dermatome.7) Follicular distribution:Lesions are arranged along

hair follicles.

Shows the border oflesions that may be:1) Well defined border:Marked separation

between the edge ofthe lesion and normalskin.

2) Ill defined border:Difficult to identify theseparation line betweenthe lesion and normal

B)Close-up examination:

3) Circinate border:The lesion increases in size byperipheral extension and healing at the

centre.

Types of Skin LesionsSkin lesions may be:

1-Initial lesions.2-Secondary lesions.3-Specific lesions.

A) Initial Lesions1) Macule:It is discolouration

of skin less than onecm in diameter. Iflarger than one cm,

it is called patch.

2) Papule:Solid elevation of theskin less than one cm indiameter. If more thanone cm, it is calledplaque.a) Dome shaped:

Papule with smoothconvex surface.

b) Flat topped:Papule with flatsurface. It is described

as lichenoid papule.

c) Umbilicated:Dome shaped papulewith central notch.

d) Verrucous:Papule with finemammilated surface.

3) Nodule:Elevated solid skin

lesion with dermalextension.

4) Vesicle:Fluid containing

lesion less than onecm in diameter. Iflarger than one cm,

it is called bulla.

Subepidermal separation Tense bulla

Flacid bullaIntraepidermal separation

B) Secondary Lesions

1) Pustule:It is elevated

lesion containingpus.

2) Scales:It is dry surfacedue to abnormal

keratinization.

Types of Scales:

a) Fine branny:Pytriasis versicolor

b) Greasy:Seborrheic Dermatitis

c) Lamellar:Psoriasis

Types of Scales:

d) Fish scales:Ichthyosis

e) Collarette:Pityriasis rosea

f) Horny (Keratotic):Discoid LE

3) Crust:It is driedexudate, eitherpus or blood.

4) Erosion:It is superficialepidermal loss.

5) Ulcer:

It is deep dermalloss, thus it hascharacteristic edge.

6) Fissure:It is longitudinaldiscontinuity of the

7) Atrophy:

It is thinning ofskin due to thinningof epidermis or

dermis or both.

8) Scar:It is replacement ofthe skin by fibrous

tissue.

9) Lichenification:It is a descriptive

term of 3 criteria:A) Thickening of skinB) Hyperpigmentation

C) Increased skinmarkings

3) Comedone:It is specific to acne. It

is either:A)Black head: papulewith central black spot.

B)White head: small palepapule.4) Tunnel (Burrow):

It is specific forscabies. It is a curvedline due to burrowing of

female mite to skin.

5 Target esion:It is specific to erythema

multiforme. It consists of 3zones:A)Central zone: cyanotic.B)Intermediate zone: pale.

C)Outer zone: erythematous.6) Herald patch :It is specific for P. rosea.

It has 3 concentric zones:A)Central café au lait.B)Peripheral erythematous.C)Intermediate collaretic

Examination of skin appendages

A) Examination of mucus membranes

Erosion Ulceration

White Streaks

Examination of skin appendages

B) Examination of nails

Nail Pitting Nail Discolouration

A) Examination of nails

Nail Fold

Swelling

Nail Dystrophy

C) Examination of hair

INVESTIGATIONS

There are certain investigationsspecific to the skin that can help inthe diagnosis of some skin diseases.1- Wood`s light.2- Skin scrapping.3- Patch testing.4- Immunoflourescent.5- Skin biopsy and histopathology.

1- Wood`s Light:

It is a special ultraviolet lightwhich if thrown to:-- Normal skin, it reflects deep

violet colour.- Pityriasis versicolour, it reflectsgolden yellow colour.

- Erythrasma, it reflects deep redcolour.- Tinea Capitis, it reflects brilliant

green colour.

Wood`s Light Examination

2- Skin Scrapping:It is used for diagnosis of fungalinfection of skin.

Procedure:Skin is scratched by scalpel. Theresulted scales are placed on glass

slide, then 10% KOH is added andexamined under the microscope.

Scrapping ofSkin by Scalpel

Hyphae ofDermatophytes

Skin Scrapping

Hair Sample

Endothrix Ectothrix

Positive ResultPatch Testing

Positive Immunoflourescence

5- Skin Biopsy:It demonstrates the pathological changesin the diseased area. It is usuallydiagnostic.Histology of skin (epidermal layers):1- Horny layer (stratum cornium)2- Granular cell layer (stratum granulosum)

3- Prickle cell layer (stratum spinosum)4- Basal cell layer (stratum basale)

Horny layer

Granular cell layer

Prickle cell layer

Basal Cell Layer

Basement Membrane

Melanocyte

Dermis

Histology of Skin

1-Hyperkeratosis:increased thickness

of horny layer or stratum cornium.2-Parakeratosis: retention of nucleiin horny layer or stratum cornium.

3-Hypergranulosis: increasedthickness of granular cell layer orstratum granulosum.

Pathological Terms:

4-Acanthosis: increased thicknessof prickle cell layer. Either

uniform or saw tooth acanthosis.5- Spongiosis: edema of pricklecell layer or stratum spinosum.

6-Acantholysis: loss of coherencebetween Cells of prickle cell layer

or stratum spinosum.

Pathological Terms:

Ther apy

D erm atology

Ther apy

D erm atology

Effects of Locally Applied Drugs

Antibacterial topical medications: destroy or inhibit

bacteria. Example: gentamycin, fusidic acid,

erythromycine, tetracycline, neomycin, and

chloramphenicol

Antiviral Topical Agents: destroy of inhibit viruses.

Example: acyclovir

Emollient Agents: soften skin surface. Example: cold

cream and vasline

Types of Topical Medications

Compresses: remove the crust. Example:

potassium permenganate 1/8000 and saline

Drying Agents: dry oozing skin. Example:

gentian violet 1% and microchrome 1%

Creams:They are semisolid emulsion systems containing

both oil and water. They are water miscible, cooling

and soothing, and are well absorbed into the skin.

They are used in acute oozing skin disorders.

Creams

They are semisolid preparations gelled with highmolecular weight polymers, such as methylcellulose.

They are non-greasy, water miscible, easy to apply and

wash off.

They are especially suitable for treating hairy parts of the body.

Types of Topical MedicationsTypes of Topical Medications

Paints:

They are liquid preparations, either aqueous, oralcoholic (tinctures), which are usually applied with a

brush to the skin. They evaporate, and are therefore

cooling as well as astringent and antiseptic.

They may also be used as protectives to sealabrasions.

Types of Topical MedicationsTypes of Topical Medications

Q uantity of Creams to prescribe

Factors affecting the quantity:

Type of dermatoses: acute or chronic

Base of topical medication: ointments spreadover skin more than creams

Intelligence of the patients: educated patients

usually consume smaller amounts

Q uantity of Creams to prescribe

AmountNeeded

Duration of Application

Frequencyof

Application

Surface Area

15 grams14 daysb.i.d.Hand1

30 grams14 daysb.i.d. Arm2

60 grams14 daysb.i.d.Leg3

480-960grams

14 daysb.i.d.EntireBody

1- initial lesions

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