A questionnaire-based survey was conducted among 1,499 Korean high school students between April and May 2006 to determine the prevalence of atopic dermatitis (AD). The questions were based on the International Study of Asthma and Allergies in Childhood (ISAAC) written questionnaire. Nearly half the cohort (n = 724) underwent eosinophil ratio, skin prick tests, total serum IgE levels and the methacholine challenge test. Based on the questionnaires, the lifetime and last 12-month AD prevalence was 22.2% and 11.4%, respectively. Based on diagnostic tests, these values were 18.5% and 8.4%, respectively. The adjusted odds ratio (aOR) which increased the last 12-month prevalence figures, including body mass index (aOR: 1.06); current asthma (aOR: ...