The nasal provocation test combined with spirometry establishes paradoxical vocal fold motion in allergic subjects.

Vocal cord dysfunction (also called paradoxical vocal cord motion) or paradoxical vocal fold motion (PVFM) is an event elicited by specific and nonspecific triggers in which its diagnosis is limited by the restricted number of available functional tests. This study was designed to appreciate the contribution of the spirometric changes elicited by the allergen-specific nasal provocation test (NPT) performed with Dermatophagoides pteronyssinus for the diagnosis of PVFM in subjects with known sensitization to this allergen. In total, 63 subjects with allergic rhinitis who had previously been shown to be sensitized to D. pteronyssinus and who had experienced one or more episodes of inspiratory shortness of breath underwent two spirometric tests, one before (pre-NPT) and another 15 minutes after the allergen-specific NPT (post-NPT). The forced inspiratory vital capacity (FIVC), forced inspiratory volume in 2 seconds (FIV2), and the ratio between the FIV in 1 second and FIVC (FIV1/FIVC) were measured by spirometry. The morphology of the post-NPT inspiratory loop was compared with the pre-NPT inspiratory loop. We found that 18 subjects (28.5%) showed alterations suggestive of PVFM on post-NPT spirometry (e.g., truncation and/or flattening of the inspiratory loop). The mean differences between the pre-NPT and post-NPT values for the whole group were significant using a two-tailed paired t-test for the FIVC (4.1; 95% confidence interval [CI95%], 1.4-6.8), FIV1/FIVC ratio (2.7; CI95%, 0.05-5.3), and FIV2 (7.2; CI95%, 3.4-11). Allergen-specific NPT combined with spirometry is useful to show allergen-specific laryngeal hyperresponsiveness in allergic subjects with PVFM. Brazilian clinical trial registry platform (Plataforma Brasil, CAAE 07971212.0.0000.5480).