[Skip to Navigation]

This article reports patch-testing results from July 1, 1996, to June 30, 1998. Over 3400 patients with suspected allergic contact dermatitis were evaluated and then patch tested by 12 North American Contact Dermatitis Group dermatologists with a screening series of 50 allergens purchased from Chemotechnique Diagnostics AB (Malmö, Sweden). The patients were patch tested using a standardized technique as outlined previously1 with Finn chambers (Epitest Ltd Oy, Tuusula, Finland) on Scanpor tape (Norgesplaster Aksjeselskap, Vennesia, Norway). The patches remained in place for 48 hours, and test sites were evaluated twice, initially at 48 to 72 hours and again between 72 and 168 hours after initial placement. A positive allergic patch test result was generally interpreted to be a 1+, 2+, or 3+ reaction manifested by erythematous papules, vesicles, or a spreading reaction with crust and ulceration.1,2 The relevance of the patch-test reactions were determined in combination with the patient's history and skin examination findings and were integrated to determine the diagnostic group.1