Relationship between bronchial hyperreactivity and bronchodilation in patients with allergic rhinitis

Background: Allergic rhinitis (AR) may be considered a risk factor for the onset of asthma. Recently, it has been reported that forced expiratory flow between 25% and 75% of vital capacity (FEF25%-75%) may predict a positive response to bronchodilation test in asthmatic children. Moreover, bronchial hyperreactivity (BHR) is frequently detected in AR patients. Objective: To evaluate the possible relationship between the response to bronchodilation test and methacholine challenge, also considering the FEF25%-75% values in a large group of patients with persistent allergic rhinitis. Methods: Three hundred sixty-five consecutive AR patients were evaluated. Clinical examination, spirometry, methacholine bronchial challenge, and bronchodilation test were performed in all patients. Results: Two hundred forty-one patients (66%) had "positive" results for bronchodilation test; FEF25%-75% was abnormal in 78 patients (21.4%), and 76 patients (20.8%) had severe BHR. An FEF25%-75% cutoff value of less than 58.5% of predicted may optimally (AUC 0.97) discriminate patients with both severe BHR and reversibility. Conclusion: This study confirms previous studies and increases the strength of the role of FEF25%-75% as a marker of early bronchial involvement in patients suffering from persistent allergic rhinitis. Moreover, an FEF25%-75% value less than 58.5% of predicted may suggest the co-existence of severe BHR and reversibility. Ann Allergy Asthma Immunol. 201 1;106:460-466.