Diagnosis Of Skin Diseases

Diagnosis of skin diseases By Zeinab abdel azim MD dermatology www.mansfans.com

Www.MansFans.Com

Skin

Flexible membranous tissue that forms the external covering of the body Skin makes up about 18% of an adult's weight and approximate total area of 1.5 – 2 m² It operates as a complex organ of numerous structures (sometimes called the integumentary system) performing vital protective and metabolic functions.

Www.MansFans.Com

www.mansfans.com

www.mansfans.com

Functions of the skin – – – – – –

Protection: Mechanical protection of deeper structures. Protection against light Protection against invasion by microorganisms

Heat regulation through: Evaporation of sweat. The skin is rich in blood vessels, through their constriction or dilatation heat loss is decreased or increased. Fat in subcutaneous tissue is poor conductor and prevents heat loss.

Excretion of certain substances through sweat. e.g. Na Cl, lactic acid, ammonia and some drugs. Formation of vitamin D: from ergosterol by UVR. perception of sensations as heat, cold, pain and touch. Reflection of internal feeling e.g., fear, shame and anger. Immunological functions.

Www.MansFans.Com

Diagnosis Initial history Examination Follow up history investigations

Initial history Personal Complaint Present history – Duration – Onset Mode of onset: acute (within hours), rapid (within days) or gradual (within weeks or months). Site of onset.

– Course:stationary, progressive, regressive or recurrent. – Symptoms:itching, burning, pain, anaesthesia or disfigurement.

Www.MansFans.Com

Examination

Skin examination must be done in good light. It should involve oral mucous membrane, hair, nails and lymph nodes. The following points should be noticed during examination: – Distribution – Configuration – Morphology of individual lesion

Distribution Localized: Affecting one anatomical area Generalized: affecting more than one anatomical area. Special sites: e.g. pressure areas such as elbows & knees, sun exposed areas or intertriginous areas. Distribution may be symmetrical or asymmetrical.

Distribution

Configuration Linear

Configuration Circinate

Configuration )Polycyclic) Geographic

Configuration Grouped

Configuration Discrete

Morphology of individual lesion Macule& patch  Circumscribed

change in skin color up to 0.5cm .  Larger lesion is a patch They may be: Hyperpigmented Hypopigmented Red – Erythema – Purpura

Morphology of individual lesion Macule

Macule

Morphology of individual lesion Macule

Morphology of individual lesion Papule Small, solid, elevated lesion up to 0.5cm.

Morphology of individual lesion Papule

Morphology of individual lesion Nodule Nodule: palpable, solid lesion > 0.5cm . Nodules may be located in the epidermis (B) or extend into the dermis or subcutaneous tissue (A).

Www.MansFans.Com

Morphology of individual lesion cyst A cyst is a sac that contains liquid or semisolid material

Www.MansFans.Com

Morphology of individual lesion Nodule&Cyst

Morphology of individual lesion Plaque Circumscribed area of abnormal skin formed by extension or coalescence of either papules or nodules .

Www.MansFans.Com

Morphology of individual lesion Plaque

Morphology of individual lesion

Vesicle& Bulla A vesicle is localized visible collection of fluid up to 0.5 cm in diameter A bulla is a vesicle larger than 0.5 cm.

Morphology of individual lesion

Vesicle& Bulla

www.mansfans.com

Morphology of individual lesion Pustule localized visible collection of pus.

Morphology of individual lesion Pustule

Morphology of individual lesion

Crust Crusts result when serum, blood, or purulent exudate dries on the skin surface and are characteristic of injury and pyogenic infections.

Morphology of individual lesion

Crust

Morphology of individual lesion Scale Flat plate of horny layer formed by accumulation of excess keratin.

scale

Morphology of individual lesion

Wheal Evanescent elevated oedematous erythematous lesion. Evanescent means that lesion does not persist > 48 hrs

Morphology of individual lesion Comedo  Plug of keratin and

sebum in a dilated pilosebaceous orifice. When plug is superficial →open )black) comedo. When plug is deep → closed )white) comedo. Comedo is the 1ry lesion of acne vulgaris

Morphology of individual lesion Burrow Superficial tunnel in skin caused by mite that appears as black dot at end of burrow. It is tortuous, straight or S shaped, skin coloured or grayish and 0.5-1.5cm in length. It is the 1ry lesion of scabies.

Morphology of individual lesion Non scarring alopecia loss of hair from a normally hairy area. Non scarring: with visible follicular opening.

Morphology of individual lesion Scarring alopecia Scarring alopecia : devoid of follicular opening.

Morphology of individual lesion Erosion:Localized loss of epidermis above basal layer. It heals without scar.

Morphology of individual lesion Erosion Localized loss of epidermis above basal layer. It heals without scar.

Morphology of individual lesion Ulcer Localized loss of epidermis and dermis. Ulcer may extend into SC fat. It heals with scar.

Morphology of individual lesion Ulcer

Localized loss of epidermis and dermis. Ulcer may extend into SC fat. It heals with scar.

Www.MansFans.Com

Morphology of individual lesion Excoriation Scratch that removes skin. It may be linear or circumscribed; superficial or deep.

Morphology of individual lesion Excoriation

www.mansfans.com

Morphology of individual lesion Fissure linear gap or slit in skin )crack in epidermis and dermis).

Fissure

Morphology of individual lesion Lichenfication Thickened skin e’exagerated skin marking in response to prolonged rubbing or itching

Morphology of individual lesion Lichenfication

Morphology of individual lesion Lichenification

Morphology of individual lesion Atrophy It results from loss of tissue. Epidermal atrophy manifests with loss of skin marking. Dermal atrophy manifests with depression in skin.

Morphology of individual lesion Atrophy

Morphology of individual lesion Hypertrophic Scar healing of injured skin by fibrous tissue formation. Atrophic scar with thin skin. Hypertrophic scar with elevated skin.

Morphology of individual lesion Hypertrophic Scar

Morphology of individual lesion Atrophic Scar

Morphology of individual lesion Sclerosis • Circumscribed or diffuse hardening or induration in the skin •Detected more easily by palpation than by inspection.

Follow up history Family H Medical H General symptoms Social H Relation of skin condition to – Food – Drug – Season – Physical factor H of drug intake

Follow up history Social H: – Emotional stress – Skin exposure H. in hand eczema – Birthplace – Hobbies – Economic state

www.mansfans.com

Investigations Skin biopsy Fungus investigation – ME – Wood’s light – Culture

Patch test Oral provocation test

www.mansfans.com

Pathological Terms Hyperkeratosis: Increased thickness of horny layer. Parakeratosis: Immature keratinization resulting in retention of nuclei in cells of horny layer. Acanthosis: Increased thickness of prickle cell layer. Acantholysis: Loss of coherence between epidermal or epithelial cells. Primary acantholysis occurs among unaltered cells as a result of dissolution of the intercellular substance, e.g., pemphigus. Secondary acantholysis occurs among altered or damaged cells, e.g. impetigo, viral vesicles. Spongiosis: Intercellular oedema in prickle cell layer. www.mansfans.com

Hyperkeratosis+Parakeratosis+Acanthosis

Acantholysis

Spongiosis

Www.MansFans.Com

Wood’light

Wood’light

Investigations Culture of fungus

www.mansfans.com

Patch test

Topical Therapy Active agent e.g., antibiotics Vehicle (base) e.g. liquid, powders, creams or ointments.    

Liquids: in acute weeping diseases (Solutions ,Lotions,Tincture,Paint). Creams: semisolid emulsion of oil in water used in subacute condition. Ointments: greasy base for dry hyperkeratotic or lichenified skin. Gels: Non greasy transparent, semisolid emulsions that liquify on contact with skin suitable for treating hairy parts of the body

Www.MansFans.Com

‫الحمد ل‬