Transcript Dermatitis
Dermatitis: Itchy Red Rashes Jerry Tan MD FRCP University of W estern Ontario W 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 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 Acute dermatitis erythema and edema papules, vesicles, and sometimes bullae accompanied by exudation and crusting Chronic dermatitis less erythema and edema presence of lichenification, scaling, and fissuring Contact Dermatitis = dermatitis precipitated by an exogenous agent 2 types: allergic (hypersensitivity) or irritant (direct noxious effect on skin) 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 Eg. Irritant contact hand dermatitis 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 Nickel Allergy - belt buckle Nickel Allergy - bracelet Hair dye allergy Hair dye allergy Latex allergy - goggles Adhesive allergy - bandage Allergy to leather sandal straps 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 Atopic Dermatitis = chronic pruritic inflammatory dermatosis associated with personal or family history of asthma, allergic rhinitis, conjunctivitis or atopic eczema. 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 Br J Derm 2007, 157: 441 Infantile atopic dermatitis Infants develop an itchy vesicular eczema on cheeks and hands often with secondary infection. scaling erythema fissures 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. Flexural involvement xerosis excoriations Erythematous patches, fissures hyperpigmentation Lichenification Accentuation of normal skin markings Adult atopic dermatitis In adults most common manifestation: hand dermatitis. chronic severe form of generalized and lichenified atopic eczema. Hand dermatitis Widespread chronic atopic dermatitis Complications of atopic dermatitis Infection: Bacterial infection: impetigo Viral infection eczema herpeticum (HSV) widespread mollusca Cataracts Growth retardation Impetiginised dermatitis Golden yellow crust Impetiginised dermatitis Fragile bullae with crust and erosions = bullous impetigo Eczema Herpeticum Extensive facial erosions More tender than typical eczema Mollusca Contagiosa Dome-shaped 1-2mm firm papules 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 Topical Steroid Classification Potency Products Comments Low Hydrocortisone acetate 1% Desonide Facial and intertriginous regions Elidel* equivalent Moderate Betamethasone valerate Triamcinolone acetonide Mometasone Protopic* 0.1% equivalent Strong Amcinonide Betamethasone dipropionate Ultra Clobetasol, Halobetasol Limit use to max 1 wk/ mth Reassess frequently *Non-steroidal antiinflammatory medications 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. Seborrheic dermatitis •Persistent erythematous patches with greasy scales •Characteristic distribution: sides of nose, glabella, perioral region, scalp, eyebrows, ears; chest. Seborrheic dermatitis Truncal seborrheic dermatitis 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 Nummular Eczema Distinctive eczema with itchy coin-shaped macules/patches typically affects limbs of middle-aged or elderly Management: emollient, topical steroid Nummular Eczema 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 Stasis eczema Stasis eczema 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 1st; +/- mild steroid ointments Xerotic dermatitis What unique features are associated with different types of dermatitis? Distinctive morphological features of different forms of dermatitis type Features of dermatitis Other skin findings atopic Symmetry, changes with age xerosis seborrheic Greasy scale, face and scalp affected oiliness nummular Coin-shaped or discoid macules and patches xerosis stasis Affects lower legs, ankles Edema, hyperpigmentation xerotic Mild, widespread; typically fall & winter allergic contact sites of contact, may have geometric patterns irritant contact typically affects hands, face xerosis Xerosis, fissuring 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 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