Patch testing in discoid eczema.
Fifty patients of both sexes with clinically suspected discoid eczema were patch tested with the Indian Standard Patch Test Battery approved by the Contact and Occupational Dermatosis Forum of India (CODFI). Most of these patients were young adults between 20 and 39 years old, with a mean age of 36 years. The mean duration of symptoms was 21/2 years. The occupational profiles of the patients included farmers (24%), housewives (18%), students (14%), housewives engaged in farming (12%), shopkeepers (10%), and laborers (8%). The miscellaneous group, including technicians, drivers, cable operators, office workers, and computer operators, accounted for the remaining 14%. The common clinical patterns of presentation of discoid eczema included hands and feet (44%), hands and forearms' (30%), legs and feet (12%) and trunk and limbs (12%). Patch test analysis of these patients revealed that, out of the 50 subjects tested, 28 (56%) reacted to one or more allergens. Potassium dichromate was the most common allergen (20%), followed by nickel (16%), cobalt chloride, and fragrance (12% each) in decreasing order of frequency. Hence, it may be concluded that patch testing should be considered for all patients with severe or persistent discoid eczema because allergic contact dermatitis may be relatively common in such patients and the avoidance of offending allergens may be of substantial benefit to the patients.