Cosmetic dermatitis in Chinese eczema patients patch tested with a modified European standard series of allergens.

The prevalence of cosmetic allergic contact dermatitis (CACD) in Chinese eczema patients (CEP) has not been reported. The purpose of our study was to analyse CACD in CEP and examine the frequency of patch test (PT) reactions to common cosmetic-related allergens (CRA). 378 consecutive CEP patch tested with a modified European standard series of allergens during a 2-year period in our clinic were analysed. 73 patients (19.3%) were considered as suspected CACD and 37 patients (9.8%) were confirmed. The frequencies of the positive PT reactions in suspected CACD and confirmed CACD to at least 1 CRA were 64.4% and 89.2%, to para-phenylenediamine (PPD) were 31.5% and 59.5%, to fragrance mix (FM) were 27.4% and 32.4% and to imidazolidinylurea were 5.5% and 8.1%, respectively. These results were much higher than those of CEP without cosmetic reactions (26.3% for at least 1 CRA, 5.8% for PPD, 8.8% for FM, and 0 for imidazolidinylurea) (P < 0.01 for all, Chi-square test and Fisher's exact test). These results suggested that CACD is very common in CEP patch tested. PPD and FM are the leading allergens identified. CACD should be strongly considered in CEP with positive PT reactions to PPD, FM and imidazolidinylurea.