Background: The mechanisms through which rhinitis affects asthma have not been completely elucidated. We explored whether the effect of nasal treatment on asthma control and respiratory-related quality of life (HRQoL) is mediated by inflammatory changes of the upper and lower airways.
Methods: Allergic rhinitics with mild asthma were randomized to a 14-day treatment period with either nasal budesonide 100 μg, 1 puff per nostril twice a day, or placebo. Clinical, functional, and biological evaluations were performed before and after treatment.
Results: Twenty subjects (M/F: 10/10; age: 31 ± 15 years; mean ± SD) were enrolled, and a total of 17 individuals completely participated in the study. Lung function was within the normal range. The total asthma control test (ACT) score was 20 ± 5.3 and the RHINASTHMA Global Summary (GS) was 44 ± 15. The percentage proportion of eosinophils in nasal lavage was 9.9% and significantly correlated with spirometric parameters reflecting peripheral airway function (for FEF(50): r = 0.48, p = .03; for FEF(25): r = 0.47, p = .03). The pH of the exhaled breath condensate (EBC) was 7.33 ± 0.4. After nasal treatment, the percentage proportion of eosinophils fell significantly (p = .002), and changes in percentage proportion of eosinophils were associated with changes both in the ACT score (r = 0.76, p = .04) and in the RHINASTHMA GS (r = 0.77, p = .02). The increase in the pH of the EBC was not associated with changes in the ACT score or with the RHINASTHMA GS.
Conclusions: These findings confirm that, in subjects with allergic rhinitis with mild asthma, nasal inflammation impacts on asthma control and HRQoL. The improved control of respiratory symptoms obtained with nasal corticosteroids seems to be mediated by functional changes in the peripheral airways.