Contact sensitization in patients with chronic venous leg ulcers in Singapore

Contact sensitization rates are high in patients with chronic venous leg ulcers. Allergic contact dermatitis poses a significant hindrance to the healing of the wounds. There are no published studies examining the rate of contact sensitization in Asian patients. Our objective was to determine the rate of contact sensitization in patients with chronic venous leg ulcer in Singapore and the variation in the common allergens based on local practices in comparison with Western countries. 44 patients were patch tested to the National Skin Centre standard series, steroid series, medicaments, topical Chinese medicaments, and to modern wound dressings used. The overall rate of contact sensitization was 61.4%. The common allergen groups were topical antibiotics (18.2%) and topical traditional Chinese medicaments (TTCM) (15.9%). Individually, colophony (11.3%), Saw Hong Choon skin ointment (Kam Bo Med, Hong Kong, Hong Kong) (11.3%), Balsam of Peru (9.1%), and povidone iodine (9.1%) were among the most frequent allergens. The sensitization rate among users of TTCM was notably high (41%). A high rate of contact sensitization was found in our study, similar to previous reports from the West. TTCM play a major role as possible allergens in our patients. In Asian patients, a history of its usage should be elicited, and patch testing should include the commonly used TTCM where possible.