Dermatology Board review

1. Dermatology Board review Dinesh Thekke, MD 08/26/2008

2. Atopic dermatitis (Eczema) 3 phases on the basis of the age of the patient • Infantile phase • Begins at 1-6 mo, and lasts for 2-3 yrs • Red, itchy papules and plaques • Oozing and crusting • Cheeks, forehead, scalp, trunks • Extensor surfaces

3. Childhood eczema Between ages 4-10 yrs Dry, papular Intensely pruritic Wrists, ankles, cubital/ popliteal fossae (flexor) Secondary infections 75% improve between 10 – 14 yrs

4. Eczema (Adult phase) • Begins around age 12; continues indefinitely • Flexural areas of arms, neck and legs • Marked lichenification may be present

5. Associated findings in Eczema • Xerosis • Ichthyosisvulgaris (Fish like scales, AD inheritance) • Keratosispilaris • Dennie- Morgan lines • Dyspigmentation (hypo- or hyper-) • Altered cellular immunity? • Infections: Staph. aureus, HSV (eczema herpeticum), Molluscumcontagiosum

6. Atopic dermatitis: treatment • Hydration/ lubrication of skin using emollients • Avoidance of predisposing factors • Antipruritic agent (Antihistaminics) • Topical steroids (mild- to moderate potency) • Topical Pimecrolimus (immunomodulators; ≥ 2 yrs) • Treatment of infections (topical/ PO anti-Staph. Abx)

7. Dyshidrotic eczema Chronic, recurrent, pruritic, vesicular eruption Palms, soles, fingers, toes Hyperhidrosis, water exposure Nummular eczema Acute, papulovesicular Coin shaped, circumscribed Extensor thighs, abdomen Lack of central clearing Resistant to therapy

8. Irritant dermatides, may be associated with eczema Lip licking eczema Thumb sucking eczema

9. Diaper dermatitis • Irritant • Candidal • Staphylococcal • Seborrheic • Psoriatic • Tinea

10. Irritant diaper dermatitis • Failure to change diapers frequently • Fecal bacteria split urea (in urine) to form ammonia • Harsh soaps, detergents, diarrhea • Convex surfaces of perineum, abdomen, thighs, buttocks • Spares intertriginous areas • Tx: frequent diaper changes, barrier pastes, topical steroid

11. Candidal diaper dermatitis • Bright red, sharp borders, and satellite lesions • Intertriginous areas are involved • KOH prep: budding yeast and pseudohyphae • Associations: Oral thrush, abx therapy • Tx: Topical antifungal

12. Staphylococcal diaper dermatitis • 20 to irritant DD or as 10 lesions • Thin walled pustules on an erythematous base • Ruptured pustules  collarette of scaling • Diagnosis: Gram stain • Tx: Topical/ PO abx

13. Seborrheic diaper dermatitis Salmon colored lesions, with yellowish scale Prominent in intertriginous areas Satellite lesions absent Seborrheic dermatitis commonly seen

14. Psoriatic diaper dermatitis • May be the initial presentation of psoriasis • Erythematous scaling eruption , clinically indistinguishable from seborrheic DD • Scales not as prominent as other forms of psoriasis • Suspect if seborrheic DD does not respond to Tx

15. Tinea diaper dermatitis • Less common • Scaly perineal rash, with active border • Diagnosis: KOH preparation • Tx: Topical antifungals

16. Contact dermatitis • Irritant CD • Caustic agents (acids, alkalis) • Anyone exposed will develop irritant CD • Acute well demarcated erythema, crusting, blisters • Allergic CD • Type 4 delayed HS reaction; T-lymphocyte mediated • Only in susceptible individuals • Poison ivy – Rhus dermatitis • Most common allergic CD in US • Linear streaks of erythematous vesicles • Direct contact with sap (leaves, stem, roots) • Other allergens: Nickel, dyes, neomycin, etc.

17. Contact dermatitis: Treatment Localized disease may respond to topical steroids Systemic steroids- Indications Widespread reaction Involvement of eyelids, face, genitals, hands 2 week tapering course of steroids Nickel CD: Avoidance Painting watch buckle with clear nail polish!

18. Psoriasis • Red well-demarcated plaques covered with dry, thick silvery scales • Extensor surfaces, scalp, buttocks • Guttate psoriasis associated with GAS (β-hemolytic) • Infants: persistent diaper dermatitis • Nail changes: plaques in nail bed, pitting, hyperkeratosis • Auspitz sign (bleeding points upon scale removal) • Koebner phenomenon: lesions at sites of injury • Remissions and exacerbations, except in Guttate psoriasis, which is self limited

20. Tinea Corporis (Dermatophyte) • Superficial infection of non-hairy (glabrous) skin • “Ring worm:” Annular lesion with central clearing and active border made of microvesicles • Pruritic red papules papulosquamous lesions • Autoinfection common due to scratching • Trichophyton tonsurans • Confirmed by KOH prep. (loose scales from margin): True hyphae(long, branching, septate rods) • Tx: Topical antifungal creams

22. Erythema multiforme (EM) • Acute hypersensitivity syndrome (drugs, viruses, bacteria, food, immunizations, CT disorders) • HSV is most common cause for recurrent EM • Symmetrical; any part of body (dorsum of hands/ feet, extensor aspect of arms & legs, palms and soles) • Dusky red macule/ wheal  iris/ target shaped lesion • Less pruritus than pain and tenderness (cf. urticaria) • Crops that persist for 2-3 weeks • Sparing of mucous membranes; systemic manifestations mild (cf. SJS) • Self limited course

24. Stevens Johnson Syndrome & TEN • Widespread epidermal and mucous membrane necrosis • ? HS to drugs, viruses, CT disorder, malignancy, etc. • Plane of cleavage below the basement membrane full thickness vesicles/ bullae (cf. SSSS: thin walled bullae) • SJS: 10-30%; TEN: 30-100% of BSA affected • Prodrome (fever, sore throat) diffuse erythroderma necrosis 24-48 hrs later hemorrhagic blistering • Nikolsky’s sign • Mucous membrane involvement (eyes-corneal scars, ectropion, oral, urethral) scarring • Prominent constitutional symptoms • Supportive management; ?IVIG. No steroids

26. Thank you