Background: 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.Objective: 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.Methods: 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.Results: 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 ≤ 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.Conclusion: 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 ≤ 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.