Objective: Attention Defi cit Hyperactivity Disorder (ADHD) is a common childhood problem similar to allergic disorders. Th e aim of the study is to determine whether allergic disorders and atopy are associated with physician-diagnosed ADHD.

Materials and Methods: This study was designed as a nested casecontrol study. One hundred sixty children were divided into three groups; 55 patients with ADHD, 55 children of healthy siblings of the study group and 50 unrelated healthy children. For each subject, an International Study of Asthma and Allergies in Children (ISAAC) questionnaire was completed. Th e total eosinophil count, total IgE levels were measured and skin prick tests were performed.

Results: The prevalence of asthma was significantly higher in the ADHD group than the control group but was similar to the sibling group. Even though prevalence of rhinitis was signifi cantly higher in ADHD group relative to the other groups, atopic rhinitis was similar in all groups. Th ere were no signifi cant diff erences for prevalence of eczema, elevated total IgE levels, eosinophil count and positive skin prick testing between any of the groups.

Conclusion: The rhinitis seems to be a risk factor for ADHD while atopic status does not appear to be involved. Nasal obstruction and sleep disturbances due to rhinitis may aff ect the cognitive functions of individuals with ADHD. Th ese individuals should be evaluated to determine whether or not (allergic) rhinitis accompanies ADHD.