Bronchial hyperresponsiveness in pediatric rhinitis patients: the difference between allergic and nonallergic rhinitis.

BACKGROUND: Numerous studies have examined the relationship of bronchial hyperresponsiveness (BHR) to asthma or allergic rhinitis (AR). However, little is known regarding the association between BHR and nonallergic rhinitis (NAR). This study investigated the prevalence and risk factors of BHR in pediatric patients with rhinitis and analyzed the difference between patients with AR and those with NAR.
METHODS: A total of 227 subjects with rhinitis aged 6-15 years underwent a parental survey and laboratory tests, including skin-prick test and methacholine challenge test. Outcome variables were analyzed in relation to BHR.
RESULTS: The prevalence of BHR was 55.7 and 25.5% in patients with AR and those with NAR, respectively. The persistency of rhinitis, blood eosinophil count, and baseline lung function were significantly associated with BHR in patients with AR, whereas individual or familial medical history, environmental factors, the serum immunoglobulin E level, the number of sensitized allergens, and the wheal size ratio of allergen to histamine did not affect the BHR rate. In multivariate analysis, the persistency of rhinitis was the only significant predictor of BHR in AR patients. However, persistent rhinitis symptoms did not increase the risk of BHR in NAR patients.
CONCLUSION: BHR occurs over two times more frequently in children with AR than in those with NAR. In addition, persistent nasal inflammation appears to increase the risk of BHR only in the presence of atopy.