Relationship between Nasal and Bronchial Responsiveness in Perennial Allergic Rhinitic Patients with Asthma

Abstract

Background: Thenasal and bronchial mucosa present similarities and mostpatients with asthma also have rhinitis, suggesting the concept of ‘one airway one disease’. Although many studies may suggest the relationship between nasal and bronchial responsiveness in patients with allergic rhinitis and asthma, few studies have been published which address this question directly. The aim of this study is to investigate whether the relationship between nonspecific nasal and bronchial responsiveness exists in perennial allergic rhinitic patients with asthma. Methods: Fifty-one perennial allergic rhinitic patients with the definitive or suspected asthma underwent methacholine bronchial provocation tests and nasal histamine challenge tests. A slope of the absolute changes in nasal symptoms score/log concentrations of histamine was calculated by linear regression analysis. A ratio of the final absolute change in nasal symptoms score to the sum of all the doses of histamine given to the subject was also calculated. The degree of bronchial responsiveness to methacholine was categorized as positive bronchial hyperresponsiveness (BHR) if PC₂₀ (provocative concentration of methacholine resulting in 20% fall in FEV₁) was <4 mg/ml, borderline BHR if PC₂₀ was ≧4 but ≤16 mg/ml, and negative BHR if PC₂₀ was >16 mg/ml. Another index of bronchial responsiveness (BRindex) was calculated as the log [(% decline in FEV₁/log final methacholine concentration as mg/dl) + 10]. Results: The geometric means of the slope (4.47 vs. 2.95, p < 0.05) and the ratio (1.68 vs. 0.54, p < 0.01) were higher in patients with positive BHR (n = 23) than in patients with negative BHR (n = 19), respectively. The geometric means of the slope (3.50) and the ratio (1.13) in patients with borderline BHR (n = 9) were between the two groups, respectively. In all patients, the log-slope (r = 0.48, p < 0.001) and the log-ratio (r = 0.51, p < 0.001) were correlated well with the BRindex, respectively. Even in allergic rhinitic patients with definitive asthma, the log-slope was correlated with the BRindex (r = 0.39, p < 0.05) or log-PC₂₀ (r = –0.36, p < 0.05). Conclusions: The nonspecific nasal responsiveness may be related to the nonspecific bronchial responsiveness in patients with allergic rhinitis and asthma, which may support the viewpoint that allergic rhinitis and asthma represent a continuum of inflammation involving one common airway.