Role of vascular reflex in nasal mucosal swelling in nasal allergy

In patients with nasal allergy, antigen challenge on the unilateral nasal mucosa results in nasal secretion not only in the ipsilateral but also in the contralateral nasal cavities that can be inhibited almost completely by premedication with atropine sulfate. The present study was performed to elucidate if centrally mediated vascular reflex induced by antigen challenge plays a role in nasal mucosal swelling in subjects with nasal allergy.

Variations of mucosal swelling and mucosal blood flow in the ipsilateral and the contralateral nasal cavities after unilateral antigen challenge were evaluated by acoustic rhinometry and laser Doppler flowmetry in 20 patients with perennial nasal allergy.

Unilateral antigen challenge caused ipsilateral and contralateral nasal mucosal swelling in 17 and 13 patients, respectively. Incidence of contralateral nasal mucosal swelling after unilateral antigen challenge was significantly higher compared with that after control disc challenge (P < .001). In 10 patients in whom unilateral antigen challenge caused bilateral nasal mucosal swelling, significant swelling of the nasal mucosa lasted for more than 30 minutes in the ipsilateral nasal cavity after antigen challenge compared with only 15 minutes in the contralateral nasal cavity. Peak values of contralateral mucosal swelling were 45.3% of those of ipsilateral nasal mucosa.

Centrally mediated vascular reflex is partially involved in the onset of nasal mucosal swelling observed after antigen challenge in subjects with nasal allergy. However, nasal mucosal swelling that persists and proceeds even 20 minutes after antigen challenge is caused by the direct effects of chemical mediators on the nasal vasculature.