Nasal hyper-responsiveness to histamine, methacholine and phentolamine in patients with perennial non-allergic rhinitis and in patients with infectious rhinitis.

Recently it has been shown that patients with atopic rhinitis and with an allergy to house dust mites have a stronger nasal response to insufflation of histamine, methacholine and phentolamine than a control group. This hyper-responsiveness could not be demonstrated in patients with perennial non-allergic rhinitis, unless the patients were selected according to the predominant symptoms in the history. Patients with rhinorrhoea ('runners') proved to be hyper-responsive to methacholine compared with normal controls. The existence of two subpopulations was emphasized by hyper-responsiveness to both histamine and methacholine in the runners group compared with the patients with a stuffy nose ('blockers'). Patients with chronic nasal infections (characterized by recurrent episodes of purulent discharge) showed no hyper-responsiveness at all, indicating that either hyper-reactivity does not play an important part in this patient population or methods to detect hyper-reactivity in this group are inadequate. In contrast to our earlier observations in patients with atopic rhinitis, increased responsiveness to phentolamine could not be detected either in the patients with perennial rhinitis or in the patients with infectious rhinitis, indicating that the possible alpha-adrenergic dysfunction found in patients with atopic rhinitis is restricted to this group.