North American Contact Dermatitis Group patch-test results, 1998 to 2000.

BACKGROUND Patch testing is the most worthwhile diagnostic tool for the evaluation of patients with suspected allergic contact dermatitis. OBJECTIVE This study reports patch-testing results from July 1, 1998, to December 31, 2000, by the North American Contact Dermatitis Group. METHODS Patients were tested with the same screening series of allergens, using a standardized patch-testing technique. The data from these patients were recorded on a standard computer entry form and analyzed. RESULTS Fifty allergens were tested on over 5,800 patients. Amidoamine, benzophenone-3, and iodopropynyl butylcarbamate were the new allergens. The top 10 allergens in frequency of positive reactions were identical to those of our 1996-to 1998-study period. The incidence of allergic nickel reactions continues to go up, leading all the test substances by 16.2%. CONCLUSION Our findings reinforce the need for a more comprehensive group of diagnostic allergens than is found in the T.R.U.E. TEST, which is sold in the United States.