Nasal provocation test using allergen extract versus cold dry air provocation test: Which and when?

Background: Nasal provocation tests (NPTs) are useful for evaluation of patients with allergic rhinitis. The cold dry air (CDA) provocation test is useful for evaluation of patients with nonspecific nasal hyperreactivity (NHR). This study aimed to determine whether the NPT or CDA provocation would be more useful for patients with different clinical pictures. Methods: We evaluated changes in nasal symptoms (visual analog scale [VAS]) and acoustic parameters after NPT or CDA provocation in healthy volunteers (group A, n = 27), patients with allergic rhinitis (group B, n = 20), and subjects with nonallergic rhinitis (group C, n = 26). According to their subjective cold hyperresponsiveness (SCH), we compared changes in VAS and acoustic parameters after each protocol. The correlation between results of the skin-prick test (SPT) and changes in VAS after each protocol was analyzed. Finally, we performed an analysis of correlation between NPT and CDA provocation. Results: After NPT, group B showed a larger change in VAS for rhinorrhea, sneezing, and itching (p < 0.01). After CDA challenge, the change in VAS for nasal obstruction was larger in group C (p < 0.05). Changes in acoustic parameters were larger in groups B and C after NPT (p < 0.01). After CDA challenge, the SCH+ group (n = 49) showed a larger decrease of acoustic parameters than the SCH- group (n = 24; p < 0.01). Significant correlation was observed between the size of SPT and degree of change in VAS after NPT. No significant correlation was observed between NPT and CDA. Conclusion: CDA could be an adjunct tool for evaluating NHR in patients with self-reported SCH.