Pathophysiological features of the nasal mucosa in patients with idiopathic rhinitis compared to allergic rhinitis

Background: The literature on abnormality of vasomotor responses of the nas al mucosa to cold stimulation of the skin in idiopathic rhinitis is conflic ting. The objective of this study was to elucidate pathophysiological featu res of the nasal mucosa in idiopathic rhinitis compared to allergic rhiniti s. Methods: The following were studied in patients with idiopathic rhinitis and allergic rhinitis and in normal controls: (1) threshold of the nasal r eaction to histamine; (2) inflammatory cells in nasal ravage and scraped na sal mucosal epithelium, and (3) nasal vasomotor response to cold stimulatio n of the feet evaluated by acoustic rhinometry. Results: Inflammatory cells were not found to be involved in idiopathic rhinitis. Nasal reactivity to histamine was significantly enhanced in patients with idiopathic rhinitis c ompared to normal controls, but was significantly lower compared to those w ith allergic rhinitis. The most prominent finding in idiopathic rhinitis wa s nasal mucosal swelling induced by cold stimulation of the feet. While in normal controls, cold stimulation of the feet caused mucosal contraction du e to sympathetic excitation, sympathetic nasal vasomotor response in idiopa thic rhinitis patients was significantly inhibited and caused mucosal swell ing and enhanced nasal secretion. Mucosal reactions observed in allergic rh initis were between those observed in idiopathic rhinitis and in normal con trols. Cold stimulation of the feet increased systolic blood pressure by 5- 15 mm Hg, but the degree of increase observed in the 3 groups was almost eq ual. Conclusions: The above findings indicate that patients with idiopathic rhinitis have abnormalities that inhibit sympathetic reactions and enhance parasympathetic vasomotor response at peripheral levels, possibly in the n asal mucosa.