Nasal physiological reactivity of subjects with nonallergic rhinitis to cold air provocation: a pilot comparison of subgroups.

BACKGROUND: Noninfectious nonallergic rhinitis (NINAR) is characterized by self-reported hyperreactivity to nonspecific physical or chemical stimuli. The relationship between these two classes of triggers is not well established, however. We compared NINAR subjects with predominantly physical or chemical triggers versus normal controls with respect to subjective (symptomatic) and objective (obstructive) responses to cold, dry air challenge.
METHODS: We studied 14 NINAR subjects and 10 normal controls. Exposures consisted of 15 minutes of cold dry air (0 degrees C/5% RH) or warm moist air (25 degrees C/50% RH) on two separate days a week apart. Subjects rated symptoms using visual analog scales and had their nasal airway resistance measured at baseline, immediately after, and at 15-minute intervals for 1 hour postexposure.
RESULTS: The majority of NINAR subjects reported physical triggers as more troublesome than chemical. Immediately postprovocation, the mean net proportional change in nasal airway resistance from baseline was +0.18 in NINAR (physical), +0.05 in NINAR (chemical), and -0.01 in control subjects (NS). However, a pooled linear regression by number of physical triggers (0-5) revealed a 7.5% increase in cold air-induced nasal airway resistance per trigger reported (p<0.05). Similarly, raising the criterion number of physical triggers from >or=1 to >or=2 also distinguished NINAR subjects from controls in a bivariate analysis.
CONCLUSION: Either considering self-reported physical triggers as a continuous scale (0-5) or requiring more physical triggers (>or=2 rather than >or=1) to define NINAR successfully predicts objective nasal reactivity to cold air provocation.