Atopy in subjects with a history of nickel allergy but negative patch tests

Various markers of atopy were studied in 20 subjects with a history of nickel allergy but negative patch test reactions, and compared with 2 control groups: 13 subjects with no history of nickel allergy and negative patch tests; 11 subjects with a history of nickel allergy and positive patch tests. No significant difference in the incidence of atopy was detected in the 3 groups.