Changes in airway resistance following nasal provocation.

Controversy exists on whether stimulation of the nasal mucosa results in reflex bronchoconstriction. To address shortcomings in previous experimental design, we performed double-blind randomized nasal challenges in asthmatic patients with allergic rhinitis and in controls. Using pledgets containing 10-microliters aliquots of 0.9% saline or increasing concentrations of methacholine or histamine, we were able to increase nasal resistance significantly in both groups. Only methacholine caused an increase in lower airway resistance, and this could be blunted by premedication of the nasal mucosa with phenylephrine. This suggests that the effect on lower airway resistance was due to systemic absorption. Our study does not support the existence of a nasobronchial reflex from mechanical alteration of the nasal mucosa.