Background: Nasal patency shows spontaneous variations but is also influenced by exercise and allergic conditions. These variations have not been described in detail with regard to allergy.
Objectives: The purpose of this study was to examine whether these variations are different in nonallergic subjects and in subjects with nasal allergy to pollen out of the pollen season.
Methods: We examined 12 of each type of subject in the winter on two days for seven hours in a climatic chamber with constant temperature and relative humidity, one day for examination of spontaneous variations and one day for examination of exercise response. Every 15 minutes the volume of the nasal cavities, minimum cross-sectional areas, and areas at fixed distances from the nostril were measured by acoustic rhinometry. Symptoms were scored by a questionnaire.
Results: There were more pronounced spontaneous variations expressed as the coefficient of variation of nasal volume in allergic than in nonallergic subjects (14% against 9%, P = .004). A nasal cycle was observed in four of the nonallergic subjects and three of the allergic subjects. In the postexercise period, the spontaneous variations in the nonallergic subjects were increased but decreased in the allergic subjects. Exercise increased nasal patency more in the allergic subjects but only significantly for the cross-sectional area at 3.3 cm (105% compared with 43% in the nonallergic subjects, P = .05). In contrast, pharmacologic decongestion in the allergic subjects showed a tendency to be more pronounced for the nasal cavity volume (55% increase versus 42%, P = .08). There was no difference between the groups in nasal symptom scores.
Conclusion: Allergic subjects out of the pollen season have more congested and more sensitive nasal mucosa than nonallergic subjects.