Analysis of factors influencing skin reactions to sunscreens, skin whitening products, and deodorants: Results from a large‐scale patch test dataset in China

Background Cosmetic products are widely used in daily life and can cause skin reactions. However, to date, few studies have investigated the prevalence and associated factors of skin reactions to different types of cosmetic products using patch test results. Objectives To investigate the frequency and associated factors of skin reactions to sunscreens, skin whitening products, and deodorants using patch test results in China. Methods This cross-sectional analysis used data collected during 2004–2017 at the Shanghai Skin Disease Hospital, China. Skin reactions were measured using patch tests following internationally standardized protocols. Results In total, 151 280 patch tests comprising 16 477 cosmetic products conducted in 4029 healthy volunteers were analyzed. The frequencies of skin reactions to different cosmetic products were 1.07%, 1.28%, and 4.41% for sunscreens, skin whitening products, and deodorants, respectively. With increasing age, a higher frequency of reactions to sunscreens in women (p < 0.001) and a lower frequency of reactions to skin whitening products in men (p < 0.05) were observed. In addition, men were more likely to develop skin reactions to deodorants compared to women (p < 0.05). Skin reactions were more frequent in winter (p < 0.05), which was true for different types of cosmetic products. Conclusions The frequency of patch testing for different cosmetic products was 1.07–4.41%. The effects of age, sex, and season vary among the different types of cosmetic products. We hope that these findings can offer guidance for a healthy skincare concept.