Atopic patch testing.

BACKGROUND: Atopic dermatitis is a major problem among the urban population and it can be aggravated or triggered by various allergens. Atopic patch test can be used as a diagnostic tool in characterizing patients with allergen triggered atopic dermatitis. AIMS: 1. Patch testing to reproduce an eczematous reaction by applying prick test allergens under occlusion on intact skin. 2. To find the allergen associated with atopic dermatitis. 3. To find the specific allergen which causes or exacerbates atopic dermatitis in a given subject. METHODS: Seventy five subjects with atopic dermatitis were included in our study and patch tests using prick test allergens were applied to the back. Reading was done after 48 and 72 hours RESULTS: Out of the 75 subjects tested, 47% showed positive reactions, parthenium accounted for 42% of all positive reactions. CONCLUSIONS: Epicutaneous application of prick test antigen on intact skin can produce a reaction. Parthenium is commonest allergen in Bangalore. Counselling based on patch test reports may help to reduce morbidity and improve quality of life.

Leg ulcers due to hyperhomocysteinemia.

Chronic leg ulcers are rare in young adults and generally indicate a vascular cause. We report a case of a 26-year-old man with leg ulcers of eight months duration. Doppler study indicated venous incompetence and a postphlebitic limb. However, as the distribution and number of ulcers was not consistent with stasis alone and no features of collagen vascular disease were noted, a hyperviscosity state was considered and confirmed with significantly elevated homocysteine level in the serum. Administration of vitamins B1, B2, B6 and B12, trimethyl-glycine, mecobalamine, folic acid and povidone iodine dressings with culture-directed antibiotic therapy led to a satisfactory healing of ulcers over a period of one month. Hyperhomocysteinemia must be considered in the differential diagnosis of leg ulcers in young individuals.

Relevance of patch testing in patients with nummular dermatitis.

BACKGROUND: A chronic dermatosis like nummular dermatitis may be complicated by contact dermatitis due to an impaired cutaneous barrier. This study is aimed at evaluating secondary contact dermatitis in patients with nummular dermatitis. METHODS: Patch testing with the Indian Standard Series was performed in 50 of 78 patients with a clinical diagnosis of nummular eczema. Significant reactions were graded as per ICDRG criteria. RESULTS: Significant reactions were noted in 23 of 50 tested patients. The most frequent sensitizers were colophony, nitrofurazone, neomycin sulfate and nickel sulfate (7.14% each). Reactions to antigens in topical medications, cosmetics and toiletries constituted 64.28% of all the reactions. CONCLUSIONS: Patients with nummular dermatitis are at significant risk of developing secondary allergic contact dermatitis, which contributes to the severity and chronicity of their dermatitis. Patch testing has the potential to improve the quality of life in these patients. Hence, patients with chronic recalcitrant nummular dermatitis must be patch tested.