Nasal responsiveness to methacholine stimulation in allergic rhinitis patients.

We examined the nasal responsiveness to topical methacholine application in allergic rhinitis and non-allergic chronic rhinitis patients, and in control subjects. Methacholine responsiveness was significantly higher in allergic rhinitis patients than in non-allergic patients and control subjects. In perennial rhinitis, methacholine responsiveness correlated with the severity of daily nasal symptoms and those provoked by specific allergen challenge tests. Among nasal symptoms, hyper-rhinorrhoea was found to be closely related to methacholine responsiveness. As a result of these findings, the possibility of cholinergic hyper-reactivity in allergic rhinitis patients is discussed.