PAPULOSQUAMOS ERUPTIONS 1 Pityriasis Rosea Definition: It is an acute to subacute generalised

features include a dry skin, pityriasis alba, scalp scaling and keratosis pilaris. More than 50% clear by the age of 18 months. In the remainder the pattern changes into that of childhood phase. (b) Childhood phase - Characteristically the elbow and knee flexures, sides of the neck, wrist and ankles are involved. The chronic course leads to lichenification. Eczematous lesions with vesiculation may occur, often in discoid patches. Hand eczema is not uncommon. Adult phase - There is predimonant involvement of major flexures. Other sites include lichenification of scrotum or vulva, nipple eczema and cheilitis. Vesicular or hyperke rat otic hand eczema and nummular eczema are the other manifestations. Associated features such as history of allergic disorders, dry skin, pityriasis alba, food intolerance, elevated serum IgE may all be present. Role of Staph. aureus - Many atopic patients have immunoglobulins E(lgE) against various staphylo toxins and interaction of staphylococcal antigen and specific antistaphylococcal antibodies may induce mast cell degranulation, causing itching and aggravation of dermatitis. Clinical infection is indicated by the presence of fissures, crusts, erosions or pustules. PROVOKING FACTORS: 1. Dry hyper-irritable skin with a low itch threshold which is aggravated by cold, wool fabrics and emotional factors. 2. Family tendency to IgE-mediated diseases, e.g. asthma, allergic rhinitis. 3. Increased susceptibility to bacterial, viral and fungal skin infections. ASSOCIATED DISORDERS - (a) Asthma and hay fever in about 50% of children with contact dermatitis. (b) Dry skin - in most pts. About 20%, have icthyosis vulgaris with associated keratosis pillaris and hypehinear palms. (c) Contact urticaria - Contact with tomatoes, citrus fruits, etc may induce redness, swelling and itching of perioral area or cheeks within minutes. Management CONTROL OF TRIGGER FACTORS - e. g. wearing cotton clothing, not keeping pets (animal dander is irritant to the skin), avoiding foods causing allergy, and stress. FIRST-LINE THERAPY: (a) Emmolients - Since dry skin is a major trigger in atopic dermatitis emmolients should be used after bathing. Moisturizing broken skin before bathing may be soothing. The emmolient can be reapplied as often as necessary throughout the day. (b) Topical corticosteroids - applied twice daily to inflamed areas using the weakest strength effective e.g. 1 % hydrocortisone or 0. 05% clobetasone butyrate. Addition of tar mixtures for lichenified skin. Antiseptics (e. g. clioquinol) or antibiotic (e. g. fucidin) added to corticosteroid to reduce staphylococcal contamination. (c) Antibiotics - Flares of dermatitis are often traggered by staphylococcal overgrowth hence 5-day course of erythromycin 125-250 mg q.d.s. (d) Ant i hist amines - to control itching. SECOND-LINE THERAPY - for pts who do not improve: (a) Topical corticosteroids -strength to be increased for about one week. Wet wrap technique - helps to control severe non-infected dermatitis in younger children. An inner layer of absorbent tubular banadage, soaked in warm water applied to skin covered with emmolients. An outer layer of bandage is applied and dressings left overnight. (b) Allergen management. THIRD-LINE THERAPY - (a) Primrose oil (gamolenic acid) capsules reduce itch and dryness in severe disease. (b) Ultraviolet B(UVB) therapy or psoralens plus UVA can help (c) Immunosuppressants (e. g. prednisolone, azathioprine) in adults with severely handicapping disease. Cyclosporin can rapidly stop the itch. 3. Circumscribed neurodermatitis - Due to persistent rubbing and scratching in an area, the skin is lichenified giving rise to a neurodermatitis. The original pruritic stimulus is usually unknown but the itch scratch itch cycle continues unabated. It has a predilection for sites such as the back of the neck, ankles, inner thighs, extensor surfaces of the forearms and genitalia. 4. Nummular dermatitis - It is characterised by coin-shaped eczematous plaques. It causes severe itching and is chronic, more during winter months. 5. Infectious eczematoid dermatitis - The skin in the region of an infected wound or sinus is macerated with the discharge, and will react with an eczematous reaction. The products of inflammation, i. e. the bacteria, toxins, denatured proteins together with the local medication will sensitize the skin causing an eczema-like reaction. G. Stasis dermatitis - is found in patients, with varicose veins. It usually starts with oedema around the ankels (in region of medial malleolus); trauma and itching will result in development of eczema. Secondary infection results in ulceration. D. PAPULOSQUAMOS ERUPTIONS 1 Pityriasis Rosea Definition: It is an acute to subacute generalised, self-limiting disease of suspected viral etiology, characterized by a symmetrical eruption of erythematous, maculopapular, circular, scaly lesions. Clinical features: Herald patch - is the initial circular or oval lesion noticed anywhere on the torso a week or two earlier than the generalized rash. It is a scaly patch larger than the macules to follow. Generalised rash - occurs symmetrically with the long axis parallel to the ribs on the trunk giving a characteristic Christmas tree-like arrangement on the back. They are oval macules or papules with a fawn coloured centre and a pink margin of centripetal scales. The lesions occur above the elbows and knees. The face is spared. Where there is marked