A study of the sensitization rate to cocamidopropyl betaine in patients patch tested in a university hospital of Beijing.

The prevalence of sensitization to cocamidopropyl betaine (CAPB) in China has not been reported. This study is to evaluate the prevalence of CAPB sensitization in patients patch tested in Peking University Third Hospital, Beijing. 429 consecutive patients with suspected allergic contact dermatitis were patch tested with CAPB 1.0% aqueous, 3-dimethylaminopropylamine (DMAPA) 1.0% aqueous as well as a modified European standard series of allergens from June 2005 to August 2006. 42 patients (9.8%) had a positive reaction to CAPB. 25 of them (59.5%) were considered relevant. Of those, 7 were head and/or neck dermatitis, 4 hand dermatitis, 1 cheilitis, and the other 13 patients were widespread dermatitis. 10 out of 429 (2.3%) patients reacted to DMAPA. Of those, 8 were relevant and 6 of them also reacted to CAPB. The rate of CAPB sensitization in our study is higher than previously reported elsewhere. CAPB is a common cosmetic allergen in Beijing. Both CAPB and DMAPA should be tested in patients with suspected cosmetic dermatitis.