Bronchial hyperreactivity and spirometric impairment in patients with seasonal allergic rhinitis

We previously demonstrated in a group of patients with perennial allergic rhinitis alone, impairment of spirometric parameters and high percentage of bronchial hyperreactivity (BHR). Thus, the present study aimed at evaluating a group of subjects suffering from seasonal allergic rhinitis alone to investigate the presence of spirometric impairment and BHR both during and outside the pollen season.

One-hundred rhinitics sensitized to pollen allergens only were evaluated during and outside the pollen season. Spirometry and methacholine bronchial challenge were performed.

Four rhinitics showed impaired values of FEV1 without referred symptoms of asthma during the pollen season. FEF 25-75 values were impaired in 17 rhinitics during the pollen season and in 11 rhinitics outside the pollen season (P<0.05). Fifty-four patients showed positive methacholine bronchial challenge both during and outside the pollen season. PD20/FEV1 methacholine was lower during the pollen season than outside (P<0.05). In BHR positive patients, reduced values of FVC (P<0.05), FEV1 (P<0.05), and FEF 25-75 (P<0.01) were significantly demonstrated in comparison with BHR negative rhinitics. There was a relationship between BHR degree and FEF 25-75 values only during the pollen season (P<0.001).

This study evidences that an impairment of spirometric parameters may be observed also in patients with seasonal allergic rhinitis alone during the pollen season. A high percentage of these patients had BHR. A close relationship between upper and lower airways is confirmed also in the model of pollen allergy. Thus, a careful evaluation of lower airways should be performed also in those patients with seasonal allergic rhinitis alone.