1. Dermatitis: Itchy Red Rashes Jerry Tan MD FRCP University of W estern Ontario W

2. Objectives Describe the cutaneous features of dermatitis Differentiate acute from chronic dermatitis Contrast irritant versus allergic contact dermatitis Describe the presentation of atopic dermatitis at different ages Indicate cutaneous findings that are unique for each type of dermatitis

3. Dermatitis (syn. eczema) Skin inflammation characterized by: itchy, scaly, patches of ill-defined erythema Common reaction pattern of various pathogenic pathways: Epidermal barrier disruption Type IV immune injury Combinations of the above

4. Acute dermatitis erythema and edema papules, vesicles, and sometimes bullae accompanied by exudation and crusting

5. Chronic dermatitis less erythema and edema presence of lichenification, scaling, and fissuring

6. Contact Dermatitis = dermatitis precipitated by an exogenous agent 2 types: allergic (hypersensitivity) or irritant (direct noxious effect on skin)

7. Irritant contact dermatitis More common than allergic contact dermatitis Results from chronic exposure to irritants that progressively disrupt the epidermal barrier Most common irritants are: Water Abrasives Chemicals, e.g. acids and alkalis Solvents and detergents

8. Eg. Irritant contact hand dermatitis

9. Allergic contact dermatitis Due to type IV immune response by specific allergen requires induction and elicitation phase (lag time to reaction) Common allergens eliciting contact dermatitis: nickel (affects 10% of women and 1% of men), perfumes, hair dyes, rubber latex Suspect if dermatitis shows geometric patterns

10. Nickel Allergy - belt buckle

11. Nickel Allergy - bracelet

12. Hair dye allergy

14. Latex allergy - goggles

15. Adhesive allergy - bandage

16. Allergy to leather sandal straps

17. Management Primary objective: Identify offending allergen or irritant Flare diaries; allergic contact patch testing Avoidance of allergen(s) / irritants. Treatment: Gentle cleansers Barrier creams Topical anti-inflammatory medications

18. Atopic Dermatitis = chronic pruritic inflammatory dermatosis associated with personal or family history of asthma, allergic rhinitis, conjunctivitis or atopic eczema.

19. Atopy defines an inherited tendency, present in 15-25% of the population, to develop one or more of: asthma, allergic rhinitis/conjuncitivitis, atopic eczema Cause of atopic dermatitis: defective epidermal differentiation (filaggrin mutations) and resultant impaired barrier function of the skin

20. Br J Derm 2007, 157: 441

21. Infantile atopic dermatitis Infants develop an itchy vesicular eczema on cheeks and hands often with secondary infection.

22. scaling erythema fissures

23. Childhood atopic dermatitis Children develop lesions @ antecubital and popliteal fossae, neck, wrists, and ankles. Lichenification, excoriations, and dry skin are common as well as post-inflammatory hyperpigmentation.

24. Flexural involvement xerosis excoriations Erythematous patches, fissures hyperpigmentation

25. Lichenification Accentuation of normal skin markings

26. Adult atopic dermatitis In adults most common manifestation: hand dermatitis. chronic severe form of generalized and lichenified atopic eczema.

27. Hand dermatitis

29. Widespread chronic atopic dermatitis

30. Complications of atopic dermatitis Infection: Bacterial infection: impetigo Viral infection eczema herpeticum (HSV) widespread mollusca Cataracts Growth retardation

31. Impetiginised dermatitis Golden yellow crust

32. Impetiginised dermatitis Fragile bullae with crust and erosions = bullous impetigo

33. Eczema Herpeticum Extensive facial erosions More tender than typical eczema

34. Mollusca Contagiosa Dome-shaped 1-2mm firm papules

35. Management Education Avoidance of irritants sweat, wool, pet dander Mild cleansers, frequent moisturisation Prescribe the least potent topical anti-inflammatory (steroid, TIMs) that is effective. Antibiotics (topical or oral) for infected eczema. +/- oral antihistamines for pruritus

36. Topical Steroid Classification Potency Products Hydrocortisone acetate 1% Comments Facial and intertriginous Low Moderate Strong Ultra Desonide Betamethasone valerate Triamcinolone acetonide Mometasone Amcinonide Betamethasone dipropionate Clobetasol, Halobetasol regions Elidel* equivalent Protopic* 0.1% equivalent Limit use to max 1 wk/ mth Reassess frequently *Non-steroidal antiinflammatory medications

37. Seborrheic dermatitis chronic, scaly inflammatory eruption usually affecting scalp and face Can also affect chest, and flexures (axillae, groin, and infra-mammary areas) due to overgrowth of the commensal yeast Pityrosporum ovale.

38. Seborrheic dermatitis Persistent erythematous patches with greasy scales Characteristic distribution: sides of nose, glabella, perioral region, scalp, eyebrows, ears; chest.

39. Seborrheic dermatitis

40. Truncal seborrheic dermatitis

41. Management Scalp: medicated shampoo (e.g. containing coal tar, selenium sulphide or ketoconazole) Face, trunk, flexures: imidazole or antimicrobial, often combined with low potency topical steroid eg HC 1% in Canesten Cream bid

42. Nummular Eczema Distinctive eczema with itchy coin-shaped macules/patches typically affects limbs of middle-aged or elderly Management: emollient, topical steroid

43. Nummular Eczema

44. Venous (Stasis) Eczema affects sites of stasis edema (lower legs) most patients are middle-aged or elderly Complications: ulcers, infections Management: Treatment of edema Support stockings, leg elevation, diuretics Skin treatment: emollient +/- steroid ointment

45. Stasis eczema

47. Xerotic dermatitis Diffuse background skin dryness with associated dermatitis typically affects limbs of the elderly. Aggravated by: harsh cleansers, dry winter conditions, hypothyroidism, use of diuretics Treat with emollients 1 st ; +/- mild steroid ointments

48. Xerotic dermatitis

49. What unique features are associated with different types of dermatitis?

50. Distinctive morphological features of different forms of dermatitis typeFeatures of dermatitisOther skin findings atopicSymmetry, changes with agexerosis seborrheicGreasy scale, face and scalp affectedoiliness nummular stasis xerotic Coin-shaped or discoid macules and patches Affects lower legs, ankles Mild, widespread; typically fall & winter xerosis Edema, hyperpigmentation xerosis allergic contact sites of contact, may have geometric patterns irritant contacttypically affects hands, faceXerosis, fissuring

51. Summary Describe the cutaneous features of dermatitis Differentiate acute from chronic dermatitis Contrast irritant versus allergic contact dermatitis Describe the presentation of atopic dermatitis at different ages Indicate cutaneous findings that are unique for each type of dermatitis

52. Acknowledgements References: Shear, Knowles and Shapiro Cutaneous Drug Reactions, Web MD Scientific American, Feb 2001. Lebwohl, M: Cutaneous Manifestations of Systemic Diseases, WebMD Scientific American Medicine, June 2003 update. Gawkrodger DJ. Dermatology an illustrated color text. Churchill Livingstone 2001 Illustrations: Dermatology Image Atlas: www.dermatlas.org www.dermis.net www.derm101.com