Prevalence and Clinical Features of Atopic Dermatitis in China.

Background. The epidemiology of atopic dermatitis (AD) in Chinese outpatients is yet to be clarified. Objectives. To investigate population-based prevalence and clinical features of AD in Chinese outpatients. Methods. A multicenter cross-sectional study was conducted in outpatients with eczema or dermatitis from 39 tertiary hospitals in 15 provinces. Results. This study included 682 patients diagnosed with AD, with the mean age of 28.8 ± 20.1 years and the median course of 5.3 ± 6.9 years. AD patients had more severe itching (30.4% versus 13.8%, p < 0.001) and clinically suspected bacterial infection (21.7% versus 16.1%, p < 0.001) than those of other types of dermatitis. Older patients were more susceptible to have a history of flexion dermatitis (p < 0.001), bacterial infection (p = 0.005), and severe itching (p < 0.001). Outpatients with clinically suspected bacterial infection had 3.53-fold increased risk of AD than those without it (p < 0.001). The morbidity rate of AD in the (20-25°N) region is 2.86 times higher than that in the (40-45°N) region [OR (95% CI): 0.352 (0.241-0.514), p < 0.001]. Conclusions. AD is characterized by unique clinical/demographic features. Bacterial infection and latitude region may have an impact on the incidence of AD in China.