Exercise-induced bronchospasm in children and adolescents with allergic rhinitis by treadmill and hyperventilation challenges.

BACKGROUND: Respiratory complaints after exercise are common in patients with rhinitis. Exercise-induced bronchospasm (EIB) may be one of the causes.

OBJECTIVES: To evaluate EIB prevalence in a group of children and adolescents with allergic rhinitis, to compare the treadmill running (TR) and eucapnic voluntary hyperventilation (EVH) challenge methods as diagnostic tools and to assess the association between respiratory complaints on exercise and EIB.

METHODS: Patients aged between 10 and 20 years were studied at the Pulmonology Department of the Hospital das Clínicas -UFPE- Recife, Brazil. The severity of symptoms of rhinitis and exercise-related respiratory complaints in the past year were evaluated. Challenges were performed in random sequence, no more than 72 h apart and followed international guidelines. Forced expiratory volume in the first second (FEV1) was determined before and 3, 5, 7, 10, 15 and 30 min after each challenge. A >10% reduction in FEV1 from baseline at two points after the challenge was considered sufficient to diagnose EIB.

RESULTS: Of the thirty-five subjects evaluated, thirteen (37%) showed EIB, six by both methods, three only after TR and four only after EVH (Coens' Kappa = 0.489). There was no association between respiratory complaints after exercise and EIB (p = 0.74).

CONCLUSION: A high prevalence of EIB was found in this population but only moderate agreement between the challenges used to diagnose EIB. Caution should be adopted when comparing these methods or interpreting their results interchangeably. There was no association between reported respiratory symptoms after exercise and EIB.