Impact of allergic rhinitis on asthma: effects on bronchial hyperreactivity

Remarkable relationship exists between upper and lower airways. Bronchial hyperreactivity (BHR) is a paramount feature of asthma and may be considered a strong risk factor for the onset of asthma in patients with allergic rhinitis.

This study is aimed at evaluating the presence of BHR in a large group of patients with moderate-severe persistent allergic rhinitis alone, and at investigating possible risk factors related to severe BHR.

Three hundred and forty-two patients with moderate-severe persistent allergic rhinitis were prospectively and consecutively evaluated. Clinical examination, skin prick test, spirometry and bronchial methacholine (MCH) test were performed in all patients.

Twenty-two (6.4%) patients had severe BHR, 74 (21.6%) patients had mild BHR and 192 (56.2%) had borderline BHR; 54 (15.8%) patients had a negative MCH test. The logistic regression analysis evidenced that trees and house dust mites sensitization (ORAdj: 8.1), rhinitis duration > 5 years (ORAdj: 5.4) and FEV1 < or = 86% of predicted (ORAdj: 4.0) were significantly associated with severe BHR. The discriminative ability of this model is appreciably satisfactory, being the AUC = 0.90.

This study highlights the close link between upper and lower airways and the role of some risk factors, such as tree and mite sensitization, > 5-year duration, and < or = 86% FEV1 values, as risk factors for severe BHR in patients with moderate-severe persistent allergic rhinitis alone. Therefore, BHR is frequently present in patients with chronic rhinitis and should be suspected in the presence of defined risk factors.