Background: Scarcity of standardized, comparable data on allergic diseases in schoolchildren in Turkey requires further multicenter studies based on the use of objective tools in addition to parent-completed questionnaires to improve the validity and reliability of results.

Methods: Using International Study of Asthma and Allergies in Children (ISAAC) Phase II tools, elementary schoolchildren aged 9 to 11 years were surveyed in 5 city centers in different regions of Turkey.

Results: We surveyed 6963 children from 70 schools and found that 35% had had at least 1 symptom of allergic diseases in the past year. Based on parental reports, the overall prevalence rates for wheezing, rhinoconjunctivitis, and eczema in the past year were 15.8%, 23.5%, and 8.1%, respectively. The overall frequencies of atopy, fl exural dermatitis, and bronchial hyperreactivity were 18.9%, 3.6%, and 24.2%, respectively. There were large variations in the prevalence of both symptoms and objective signs between study centers. Absence from school for at least 1 day was reported for 34.2% of children with a diagnosis of asthma or allergic rhinitis.

Conclusions: Approximately one third of elementary schoolchildren reported symptoms compatible with allergic diseases in the past year. The interregional differences in both symptoms and objective test results are possibly due to differences in environmental conditions. Unfortunately, serious problems are still encountered in the timely and proper diagnosis and treatment of allergic diseases.

Key words: Allergy. Asthma. Atopy. Childhood. Epidemiology. ISAAC. Prevalence.