The Effect of the Nasal Cycle on the Interpretation of Rhinomanometric Results in a Nasal Provocation Test

A nasal provocation test was carried out in two groups of adults: patients with birch pollen allergy (n = 25) and a group of healthy volunteers with no nasal allergy (n = 25). An endonasal provocation test was performed using increasing concentrations of birch pollen extract. The maximal duration of the test was 1 hour. The physiologic changes in the nasal patency in both groups were studied at a separate session at 10-minute intervals during 1 hour. The nasal patency was recorded with a computerized rhinomanometer using the anterior active method. The statistical analysis of the results shows that modern rhinomanometry is a reliable method of objectively evaluating the alternations in nasal obstruction during a nasal provocation test. The rhinomanometric findings correlate well with the rhinoscopic findings and the subjective symptoms of the patients. The changes in the nasal resistance values during the provocation were significantly larger than the physiologic ones. The individual biologic rhythmicity of nasal airway patency cannot hide the real positive result of a rhinomanometric provocation test, but it must be considered as an important factor in interpreting the results in nasal challenge.