Background: Allergic disorders are characterized by a systemic involvement of the immune response. There is a clear link between allergic rhinitis and asthma. Bronchial hyperreactivity (BHR) may be present in rhinitics. Smaller airways may also be impaired in mild asthma. This study aimed at evaluating a group of subjects suffering from perennial allergic rhinitis alone to investigate the presence of BHR and spirometric impairment. Methods: One hundred rhinitics sensitized only to perennial allergens were evaluated. Spirometry and methacholine bronchial challenge were performed. Results: Five rhinitics showed reduced values of forced expiratory volume/ 1 s (FEV1) without symptoms of asthma. Forty-eight rhinitics had reduced forced expiratory flow at 25 and 75% of pulmonary volume (FEF25-75) values. Seventy-two patients showed a positive methacholine challenge. In this group, reduced values of FVC ( p < 0.05), FEV1 ( p < 0.05), and FEF25-75 (p < 0.01) were demonstrated in comparison with BHR-negative rhinitics. There was a relationship between the degree of BHR and FEV1 values ( p <0.05) and FEF25-75 values (p < 0.01). Conclusions: This study evidences that an impairment of spirometric parameters may be observed in patients with perennial allergic rhinitis alone. A high percentage of these patients have BHR. Thus, new management strategies should be employed in rhinitics. Copyright (C) 2004 S. Karger AG, Basel.