Epidemiology of atopic dermatitis in adults: Results from an international survey.

BACKGROUND: There are gaps in our knowledge of the prevalence of adult atopic dermatitis (AD). OBJECTIVE: To estimate the prevalence of AD in adults and by disease severity. METHODS: This international, cross-sectional, web-based survey was performed in the United States, Canada, France, Germany, Italy, Spain, United Kingdom, and Japan. Adult members of online respondent panels were sent a questionnaire for AD identification and severity assessment; demographic quotas ensured population representativeness for each country. A diagnosis of AD required subjects to be positive on the modified UK Working Party/ISAAC criteria and self-report of ever having an AD diagnosis by a physician. The proportion of subjects with AD who reported being treated for their condition was determined and also used to estimate prevalence. Severity scales were Patient-Oriented SCORAD, Patient-Orientated Eczema Measure, and Patient Global Assessment. RESULTS: Among participants by region, the point prevalence of adult AD in the overall/treated populations was 4.9%/3.9% in the US, 3.5%/2.6% in Canada, 4.4%/3.5% in the EU, and 2.1%/1.5% in Japan. The prevalence was generally lower for males vs females, and decreased with age. Regional variability was observed within countries. Severity varied by scale and region; however, regardless of the scale or region, proportion of subjects reporting severe disease was lower than mild or moderate disease. CONCLUSIONS: Prevalence of adult AD ranged from 2.1% to 4.9% across countries. Severe AD represented a small proportion of the overall AD population regardless of measure or region.