INTRODUCTION TO DERMATOLOGY

Important functions of the skin Dermatology deals with disorders of skin, hair, nails, and mucous membranes. Important functions of the skin Protection against external injury Fluid balance Temperature organ Synthesis of Vit D Part of immune system (e.g. langerhan’s cell) Cosmetic function.

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).

Structure of skin Epidermis Basement membrane (dermoepidermal junction) Dermis Subcutaneous fat Epidermis: Four layers (from outside – inside) Cornified layer Granular layer Spinous layer Basal layer Dermis contains: Collagen fibers Elastic fibers Ground substances Blood vessels Nerves.

Skin appendages: Hair follicle Sebaceous gland Arrector pili muscle Eccrine sweat gland Apocrine sweat glands Nail

Dermatological History age, sex Chief complaint : + duration itching burning pain History of present illness When and how started? Mild, moderate or severe? Aggravating or reliving factors? Any other symptoms Review of systems Past medical history Drug history

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

Primary Lesions Secondary lesions Macule Crust Papule Erosion Plaque Scale Nodule Ulceration Cyst Excoriation Wheal Scar Vesicle Atrophy Bulla Fissure Purpura Necrosis Burrow Lichenification Telangectasia

Primary skin lesions

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).

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)

Nodule Palpable solid deep lesion (depth> diameter) - Epidermal

Plaque A slightly raised lesion greater than 1 cm in diameter Papules confluence (psoriasis) Patch thickening (mycosis fungoides)

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

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

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.

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

Cyst: palpable soft sac containing fluid. - Epidermal - Dermal

Telangiectasia Dilatation of capillaries gives rise to this skin condition.

Secondary skin lesions

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

Excoriation A haemorrhagic excavation of the skin resulting from scratching.

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

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

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

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

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

Erosion A partial break in the epidermis is known as an erosion It heals without scarring unless secondary infection occurs. Commonly following a blister

Ulcer An ulcer is a full-thickness loss of the epidermis Heals with scarring

FISSURE a linear cleavages or cracks in the skin.

Atrophy Thinning and transparency of the skin Caused by diminution of the epidermis, the dermis, or both Wrinkling and translucency

Sclerosis A circumscribed or diffuse hardening or induration of the skin A result of dermal or subcutaneous edema, cellular infiltration, or collagen proliferation

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

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)

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.

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

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)

Colour in Dermatology Red:Vascular lesions e.g. port wine stain also, inflammatory disorders like psoriasis Blue: Blue nevus Mongolian spot Yellow: Xanthoma White: Vitiligo Black: Melanocytic nevus & melanoma Purple or (Violaceous) : Lichen planus

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).

Nikolsky sign

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

Additional skin examination: ~Wood’s Lamp: Produces long wave ultraviolet light(UVA). e.g. Vitiligo  milky white Tinea Versicolor  golden Tinea Capitis (caused by microsporum)  yellow green Erytherasma  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.

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

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 vulgaris 2.Multinucleated giant cells in herpes simplex, zoster or varicella Viral culture

important in immunobullous disorder 1. Direct : use pt’s skin Skin biopsy : Under local anasthesia, different types: Punch Shave Excisional Incisional Immunofloursence : important in immunobullous disorder 1. Direct : use pt’s skin 2. Indirect: use pt’s Serum Prick test Patch test

Treatment: Topical corticosteroids Mechanism of action 1. Anti-inflammatory 2. Anti-proliferative 3. Vascoconstrive 4. Immunosuppressive

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. 1

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

Topical steroids (cont’d) Various formulations: Ointment, cream ,gel, solution, lotion Side effects (if used for long period and at inappropriate site): Atrophy , Acne Telangectasia, 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

Topical retinoids (vit.A derivatives) 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)

*Topical vit. D analogues calcipotriene (daivonex).Used in psoriasis Main 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

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.

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)

Physical methods -Cryotherapy : e.g. Liquid Nitrogen used in treatment of warts -Electrcautery -Sclerotherapy for varicose viens -Curettage

Oral Medications Systemic steroids: The most commonly used is prednisolone What are the S/E ? DM ,Wt gain HTN HPA axis suppersion Osteoprosis, Avascular necrosis Pyschosis,Depression etc…. How to prevents them? Monitor BP, blood sugar Vit. D. ,Calcium supplement

Oral Medications Antibiotics: Pencillins Cephalosporins Macrolides Fluoroquinolones Tetracyclines Anti-TB Anti- Leprosy

Oral Medications Antiviral Acyclovir Famcilovir Valacyclovir Antifungal : e.g. Terbinafine Griseolfulvin Itraconazole Ketoconazole Antiviral Acyclovir Famcilovir Valacyclovir

Oral Medications *Immunosuppressive and antiproliferative Azathiopurine (imuran) Cyclosporin-A Mycophenolate Mofetil Cyclophosamide Methotrexate *Antimalaria * Interferones *Systemic Retinoids e.g. Isotreitonoin, used in acne Acitertin used in psoriasis S/E?(elevate LFT and Lipids,also Teratogenic)

Oral Medications Antihistamine:for itching -sedating(e.g.Hydroxyzine,Chlorphenarmine) -non sedating(e.g Loratidine and Cetrizine) Antiandrogens Psychotropic Colchicine Potassium iodide Emoillents Sunscreen : Chemical and physical

Phototherapy Ultraviolet light A or B with or without psoralen PUVA (psoralen + UVA) New modalities: Narrow band UVB UVA – 1 Excimer laser(308nm) Indications: psoriasis, vitiligo, atopic dermatitis,CTCL(cutaneous T cell lymphoma )etc…

Laser acronym for: Light Amplification Stimulated Emission Radiation Harmful if accidently goes to the eye. Does not induce cancer Safe for pregnant ladies Different wavelengths targeting different chromophores Types: Vascular , Pigmentary Resurfacing, Hair removal

Depth of Penetration Laser Tissue Interactions Er C02 KTP PD Ruby Alex Nd YAG When selecting the energy to be delivered to the target, two factors need to be considered: 1. The energy must be high enough to destroy the target, such as hair. 2. The energy must be below the level that would damage the surrounding tissue, in this case the skin. 1 9

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