Contact dermatitis to topical medicaments: A retrospective study from a medical center in Taiwan

Background/objective Contact dermatitis to topical medicaments is commonly encountered in daily practice of dermatologists. The incidence and ranking of common allergens in topical medicaments may vary depending on local prescription and self-medication behavior. The objective of this study is to investigate the clinical features and common allergens of contact dermatitis to topical medicaments in Taiwan. Methods From 1978 to 2005, a total of 3717 patients had been patch tested in our Contact Dermatitis Clinic. Any case with suspected contact allergy to topical medicaments receiving patch testing was included in this study. Results During this period, a total of 608 patients were included and 603 of them completed the patch tests. Of the 603 patch-tested patients, 397 (66%) were positive for at least one antigen, and all patch tests were negative in 206 (34%). Patients with positive patch testing were characterized by younger age and location on the limbs and skin folds, while sex and atopy were not different among the two groups. A total of 1076 positive reactions to identifiable medicaments or main ingredients were recorded in 397 patients with positive patch testing. Among these positive reactions, 701/1076 counts (65%) were read as relevant. Traditional herbal medicaments (50%), antiseptics (21%), vehicle ingredients (9%), antibiotics (8%), corticosteroids (2%), anesthetics (2%), and nonsteroidal anti-inflammatory drugs (1%) were the most common sensitizers in this study, and the common concomitant allergens were fragrance (52%) and metal (20%). Conclusion The results emphasized the special cultural consideration in Taiwanese patients with contact dermatitis to topical medicaments.