Prevalence of allergic contact dermatitis in Thailand

Background: Contact dermatitis is a universal condition. Patch testing is an effective diagnostic tool for clinically suspected allergic contact dermatitis. Previous studies have shown that the prevalence of specific allergens varies by geographic area. Objective: To determine the relative frequency of positive reactions to different sensitizers in Thai patients with clinically suspected contact dermatitis. Methods: The results of patch tests performed from January 1, 2004, to December 31, 2006, at the Siriraj Hospital Contact Dermatitis Clinic were analyzed. A total of 323 consecutive patients (83% women and 17% men, with mean age of 39 years) were patch-tested with the total number of allergens used from both European standard patch test series and International patch test series was 26. Results: The most frequent allergen was potassium dichromate (27%), followed by nickel sulfate (26.6%), fragrance mix (20.7%), and cobalt chloride (16.4%). Conclusions: We compared the results with published findings in Asian-Pacific populations to identify geographic cultural differences in the prevalence of the allergens. The findings of the present study are able to identify the set of prominent local allergens for better revision of the standard patch test to local needs.