Nickel sensitivity in atopics, psoriatics and healthy subjects.

A prospective study of 552 persons was performed to study nickel allergy in atopics, with and without dermatitis, psoriatics and healthy adults. We found no statistically-significant difference in the frequency of nickel allergy between persons with atopic dermatitis, atopics without dermatitis and healthy controls. More females than men gave a history of metal intolerance and gave allergic patch test reactions. A poor correlation between history and patch test reaction was not specific for atopics. Psoriatics had a significantly lower frequency of allergic patch test reactions to nickel than healthy controls or atopics with and without dermatitis. Psoriatics should not be used as controls for atopics in studies of contact dermatitis.