The Prevalence and Risk Factors of Atopic Dermatitis and Clinical Characteristics according to Disease Onset in 19-Year-Old Korean Male Subjects.

Background: The natural course of atopic dermatitis (AD) in infancy, childhood, and adolescence is not yet completely known. Objective: To investigate the prevalence and risk factors of atopic dermatits among 19-year-old Korean male subjects. Methods: All 19-year-old Korean males must undergo medical examination for conscription. We precisely evaluated the prevalence of AD in three Korean provinces using the information from this physical checkup. AD was diagnosed by experienced dermatologists according to the Hanifin and Rajka criteria. The disease severity was assessed by the scoring of atopic dermatitis (SCORAD) index. In order to investigate the risk factors for AD, a questionnaire was administered to all subjects regarding parental atopic history, geographical characteristics of past habitation, past economic status, number of siblings, parental occupation, etc. Results: The point prevalence in the Korean provinces ranged from 1.15% to 1.44%. In multivariable analysis, a parental history of AD was a significant risk factor in all 3 disease-onset groups (infancy, childhood, and adolescent onset). In the infancy-onset group, low economic status was also a significant risk factor for AD. The SCORAD index was significantly higher in AD subjects with early onset and those living in small-sized habitations. Moreover, erythema, edema, lichenification, dryness of skin, and sleep loss appeared to be more severe in early-onset cases. Conclusion: The younger the age of disease onset, the more severe the clinical outcomes in 19-year-old male subjects. In addition, active AD treatment at younger ages might affect the prevalence and the severity of AD in adulthood.