Hyperresponsiveness of congestive nasal reflexes in allergic rhinitis

Background: Nasal secretory hyperresponsiveness is well documented in allergic rhinitis, and is mediated in part by neural mechanisms. In contrast, reflex-mediated congestion is poorly documented in both normal and allergic subjects. Objective: To characterize congestive responses to unilateral nasal bradykinin challenge in normal and allergic subjects, and to investigate whether congestive hyperresponsiveness is present in allergic rhinitis. Methods: Normal subjects (n=13), and subjects with out-of-season season al allergic rhinitis (SAR) (n=16) underwent a unilateral nasal challenge protocol using filter paper disks, using Hartman's solution and bradykinin as challenge substances. Congestive responses were measured using acoustic rhinometry. Results: Normal subjects demonstrated a tran sient ipsilateral congestive response, and a circumscribed contralateral congestive response away from the major flow limiting section. Subjects with SAR demonstrated a more persistent ipsilateral congestive response, and a more pronounced, generalized contralateral congestive response affecting all areas of the contralateral nasal cavity. Significant differences were present between normal and SAR subjects. Conclusion: Congestive re flexes are present in normal and allergic subjects. Congestive hyperresponsiveness is present in allergic rhinitis.