The relationship between bronchial responsiveness, lung function, and results of skin prick testing was studied in 527 children and adolescents from Copenhagen. All participants completed a questionnaire concerning allergic symptoms (asthma, rhinitis, atopic dermatitis, and urticaria). Furthermore, skin prick test reactivity to nine common aeroallergens, lung function, serum IgE and bronchial responsiveness to histamine and exercise were measured. A total of 53 subjects were atopic, (skin prick 3+), 105 subjects had moderate skin reactivity (1-2+), and 366 subjects had no signs of atopic disease (prick test negative); 58% of the subjects with skin test reactivity (1-3+) were asymptomatic. Increasing degree of atopy was correlated significantly with symptoms such as asthma, rhinitis, dermatitis, and urticaria (P less than .001); increasing level of IgE (P less than .001); month of birth (P = .001); and family history of allergic diseases (P less than .05). The most important markers for the degree of bronchial responsiveness to inhaled histamine were the presence of respiratory symptoms (P less than .001), the degree of atopy (P = .001), a history of asthma in at least two first degree relatives (P less than .01), and the skin reactivity to house dust mites (P = .001), horse epithelium (P = .01), Alternaria iridis, and dog epithelium (P less than .05). In contrast, the degree of bronchial responsiveness to exercise was significantly correlated with asthma (P less than .001), the level of IgE (P less than .05), month of birth (P less than .001), and birth weight (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)