Changes in skin test reactivity among adults with atopic disease: a 3-year prospective study

Background Our knowledge about longitudinal predictors of atopy is limited. Objectives To describe changes in skin test reactivity during a 3-year period in a sample of adolescents and adults with atopic disease and to identify factors of importance for these changes. Methods From a sample of 1,186 candidates, ranging in age from 14 to 44 years, who in a screening questionnaire reported symptoms suggestive of respiratory allergic disease, 344 individuals with a positive skin prick test (SPT) result concomitantly with asthma and/or rhinitis were clinically studied on 2 occasions, 3 years apart. Results In total, 134 (39% of the study population) had a different SPT result at follow-up compared with baseline, based on a diagnostic criterion of 3 mm for a positive test result; 77 (22%) developed de novo sensitizations to 1 or more allergens, 45 (13%) had remission of 1 or more sensitizations, and 12 (4%) both gained and lost sensitizations. Female sex (odds ratio=1.90 [1.02-3.57], P = .04) significantly predicted incidence of 1 or more sensitizations. Conclusions Four of 10 adults with atopic disease will have changes in SPT status during a 3-year period, and most will gain new sensitizations. Women with atopic disease are at increased risk of developing new sensitizations compared with men.