Prevalence and clinical relevance of allergic rhinitis in patients with classic asthma and cough variant asthma.

BACKGROUND A clinically relevant relationship between classic asthma and allergic rhinitis has been reported. However, the possible link between cough variant asthma (CVA) and allergic rhinitis remains unknown. OBJECTIVES To clarify the prevalence and clinical relevance of perennial allergic rhinitis or seasonal allergic rhinitis in CVA patients compared to classic asthma patients. METHODS We retrospectively studied adult patients with classic asthma (n = 190) and those with CVA (n = 83). The prevalence of perennial allergic rhinitis or seasonal allergic rhinitis and associations of concomitant perennial or seasonal allergic rhinitis with asthma severity, forced expiratory volume in 1 s (% predicted), fractional exhaled nitric oxide (FeNO) levels, and eosinophil proportions in sputum and blood were analyzed in the two groups. RESULTS The prevalence of perennial allergic rhinitis and/or seasonal allergic rhinitis was significantly higher in classic asthma patients than in CVA patients (all p < 0.05). Concomitant perennial allergic rhinitis was associated with higher FeNO levels and eosinophil proportions in sputum and blood in classic asthma patients (p = 0.035, p = 0.036, and p = 0.008, respectively) and with higher asthma severity, FeNO levels, and sputum eosinophil proportions in CVA patients (p = 0.031, p = 0.007, and p = 0.010, respectively). Concomitant seasonal allergic rhinitis was only associated with higher sputum eosinophil proportions in CVA patients with active rhinitis symptoms during the sensitized pollen season (p = 0.025). CONCLUSIONS Perennial allergic rhinitis may be relevant for CVA patients as well as classic asthma patients by consistently augmenting eosinophilic lower airway inflammation.