Relationship between bronchial hyperreactivity and bronchodilation in patients with allergic rhinitis

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 (FEF(25%-75%)) may predict a positive response to bronchodilation test in asthmatic children. Moreover, bronchial hyperreactivity (BHR) is frequently detected in AR patients.

To evaluate the possible relationship between the response to bronchodilation test and methacholine challenge, also considering the FEF(25%-75%) values in a large group of patients with persistent allergic rhinitis.

Three hundred sixty-five consecutive AR patients were evaluated. Clinical examination, spirometry, methacholine bronchial challenge, and bronchodilation test were performed in all patients.

Two hundred forty-one patients (66%) had "positive" results for bronchodilation test; FEF(25%-75%) was abnormal in 78 patients (21.4%), and 76 patients (20.8%) had severe BHR. An FEF(25%-75%) cutoff value of less than 58.5% of predicted may optimally (AUC 0.97) discriminate patients with both severe BHR and reversibility.

This study confirms previous studies and increases the strength of the role of FEF(25%-75%) as a marker of early bronchial involvement in patients suffering from persistent allergic rhinitis. Moreover, an FEF(25%-75%) value less than 58.5% of predicted may suggest the co-existence of severe BHR and reversibility.