Natural and induced allergic responses increase the ability of the nose to warm and humidify air.

Background: We have previously shown that subjects with seasonal allergic rhinitis out of season had a reduced ability to warm and humidify air compared with normal subjects.
Objective: We sought to investigate whether allergic reactions induced by either seasonal exposure or nasal challenge with antigen would decrease the capacity of the nose to condition cold, dry air.
Methods: We performed two prospective studies comparing the effects of allergic inflammation, induced by either seasonal exposure or nasal challenge with antigen, on nasal conditioning capacity (NCC). The total water gradient (WG) across the nose was used to represent the NCC. In the first study, the NCC was measured and compared before and during the allergy season in 10 subjects with seasonal allergic rhinitis. In the second study, 20 subjects with seasonal allergic rhinitis were recruited outside of the allergy season. NCC was measured and compared before and 24 hours after challenge with antigen.
Results: In the first study, seasonal allergic subjects in season showed a significant increase in NCC when compared with their preseason baseline (total WG in season: 2050 +/- 138 mg vs total WG preseason: 1524 +/- 100 mg; P <.01). In the second study, antigen challenge led to early-phase and late-phase responses. There was a statistically significant increase in NCC 24 hours after antigen challenge compared with that before antigen challenge (total WG after antigen challenge: 1938 +/- 101 mg vs total WG before antigen challenge: 1648 +/- 84 mg; P =.01).
Conclusion: Allergic reactions induced by either seasonal exposure or antigen challenge increase the ability of the nose to condition inspired air. We speculate that allergic inflammation increases this ability by changing the perimeter of the nasal cavity.