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 occlussion 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 72hours
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.