Bronchial hyperresponsiveness in children with atopic rhinitis: a seven-year follow-up

Background: A high prevalence of bronchial hyperresponsiveness (BHR) was found in atopic subjects with rhinitis. Those subjects may be at higher risk for developing bronchial asthma. We evaluated, in a 7-year follow-up, BHR and atopy in a homogeneous population of nonasthmatic children with allergic rhinitis (AR), and their role in asthma development. Methods: Twenty-eight children (6-15 years) with AR were studied. At enrollment (T-0), skin tests, total serum IgE assay, peak expiratory flow (PEF) monitoring and methacholine (Mch) bronchial challenge were performed. BHR was computed as the Mch dose causing a 20% forced expiratory volume (FEV)(1) fall (PD20FEV1) and as dose-response slope (D-RS). Subjects were reassessed after 7 years (T-1) using the same criteria. Results: At T-0, 13 children (46%), showing a PD20FEV1 <1526 mug of Mch, had BHR (Mch+), although PEF variability (PEFv) was within normal limits. None of the children with negative methacholine test developed bronchial asthma after 7 years. Of the 13 Mch+, only two reported asthma symptoms after 7 years. No significant change was seen in the other parameters of atopy considered. Conclusion: Children with allergic rhinitis present a high prevalence of BHR. Nevertheless, their PEFv is normal and the rate of asthma development low.