Comparison of the time course of atopic dermatitis from birth to 19 years old among generations of patients in Japan.

Atopic dermatitis (AD) mostly develops in early childhood and tends to resolve with age. However, its time course in severity before and after adolescence varies widely among patients. To investigate the course of disease severity from birth to 19 years old of adult patients with AD, we conducted a nationwide Web-based survey of 3090 Japanese adult subjects diagnosed with AD, using a questionnaire to choose a pattern that most resembled their own out of 10 courses of AD severity. Patients in the 20s and 30s age groups tended to choose the option "gradually improved" or "improved by the age of 12", but patients in the 40s or older age group tended to choose the option "aggravation between the age of 12 and 19". Those who chose "AD development at age 20 or older" increased as the generation was older. This survey revealed that the time course of AD severity from birth to 19 years old varies depending on the generation targeted in this study. It is presumed that the acquired factors affecting the natural history of AD have changed over the past 50 years in Japan.