Exercise-induced bronchoconstriction in rhinitis children without asthma.

Background: Exercise-induced bronchoconstriction (EIB) is a condition that leads to limited participation in sports. Prevalence of EIB ranges from 5-20% in general population to 40 - 90% in asthmatic patients. But the prevalence among rhinitis children with EIB remains debatable. We aimed to determine the prevalence of EIB in nonasthmatic children with rhinitis.

Methods: A cross-sectional study was performed on 53 rhinitis patients without known asthma who attended the Pediatric Allergy Clinic between March 2009 and February 2010. They all underwent physical examination, skin prick test, pulmonary function tests and an exercise challenge test (ECT) on a treadmill. A positive ECT was defined as a decrease in FEV1 > 10% after exercise.

Results: The patients' mean age was 12.3 +/- 2.6 years. Most of them (60.4%) had moderate to severe persistent rhinitis. Eleven out of 53 patients (20.7%) had EIB. The peak time for occurrence of EIB was 10 minutes after exercise. Most of the EIB episodes observed were of mild degree. Patients who had persistent symptoms and a short duration of rhinitis treatment prior to the ECT day had more positive ECT results (72.7% vs. 28.6%, p 0.013, 0.2 years vs.1.9 years, p 0.012, respectively). The history (Hx) was not a reliable means of identifying children who had EIB (ECT+/Hx+ 54.6%, ECT-/Hx+ 54.8%). There was no significant relationship between baseline pulmonary function and the decline in FEV1 after exercise.

Conclusion: The prevalence of EIB in rhinitis children without asthma is 20.7%. History, physical examination and pulmonary function are insufficient to diagnose EIB.