Short-time cold dry air exposure: a useful diagnostic tool for nasal hyperresponsiveness

Demonstration of nasal hyperreactivity (NHR) in allergic and nonallergic rhinitis remains a diagnostic challenge because of the lack of a clinically attractive protocol with high sensitivity and specificity. Our aim was to evaluate the feasibility of a shortened cold dry air (CDA) provocation protocol for the diagnosis of NHR in patients with allergic rhinitis (AR) and idiopathic rhinitis (IR).

Twelve AR patients, 12 IR patients, and 12 controls were exposed to air at -10°C and <10% humidity for 15 minutes.

Nasal symptoms were subjectively evaluated by visual analogue scale (VAS), and nasal obstruction was objectively measured by peak nasal inspiratory flow (PNIF) before and after CDA exposure. NHR was defined as a drop in PNIF larger than 20% from baseline upon CDA challenge.

Nasal CDA exposure induced nasal obstruction in AR and IR patients but not in controls. The VAS for nasal obstruction increased significantly in IR patients (post-CDA: 9.1 cm [6.9, 9.7] vs. pre-CDA: 5.5 cm [5.0, 8.9], P = .004) as well as in AR patients (post-CDA: 5.0 cm [1.3, 6.6] vs. pre-CDA: 0.8 cm [0.0, 1.7], P = .001). PNIF values showed a significant decrease in the AR (post-CDA: 50.0 L/min [37.5, 97.5] vs. pre-CDA: 95.0 L/min [52.5, 127.5], P = .002) and IR (post-CDA: 75.0 L/min [47.5, 102.5] vs. pre-CDA: 100.0 L/min [67.5, 130.0], P = .002) group after CDA provocation, which was not observed in the controls (P = 1.000). The sensitivity and specificity of CDA provocation for diagnosis of NHR were 66.7% and 100%, respectively, for both IR and AR. In contrast to nasal obstruction, rhinorrhea and sneezing were not induced by CDA exposure.

This study demonstrates that a short nasal CDA exposure is a reliable method for the diagnosis of NHR in rhinitis patients, with a high sensitivity and specificity.