The International Study of Asthma and Allergies in Childhood (ISAAC): study design and methods of phase II

Following the success of worldwide ISAAC phase I surveys subsequent ISAAC p hase II studies have started in some areas. The aim of these studies is to confirm the differences in the prevalence of atopic conditions shown in pha se I by objective measures of disease and to extend our understanding of th e determinants of childhood asthma, allergic rhinoconjunctivitis, and atopi c dermatitis. A comprehensive protocol has been developed describing the sa mpling procedure and the different methods to examine study subjects. An ex tended questionnaire asking for other respiratory symptoms, management of a ffected children, and for potential risk factors has been developed. Moreov er, child contact modules for skin examination for flexural dermatitis, ski n prick tests, bronchial challenge, blood sampling for serologic and geneti c analyses, and dust sampling procedures to measure indoor allergen levels are described. We expect that the ongoing international studies using these objective measures of disease, which apply strict quality criteria for imp lementation of the field work, and carefully assess the exposures of intere st will further contribute to our understanding of childhood asthma and all ergies in the near future.