[Prevalence of allergic rhinitis among asthmatic patients in two different seasons]

Allergic rhinitis and asthma are often comorbid, and allergic rhinitis has been shown to be a risk factor for asthma in adults and children. Recently, the prevalence of allergic rhinitis among bronchial asthma (BA) patients was reported to be 67.3% in Japan. However, seasonal variation in the prevalence of rhinitis in Japan remains unclear.

To investigate the seasonal differences in comorbid allergic rhinitis among asthmatic patients, a survey of BA outpatients aged six years and older was conducted at the Allergy Center, Saitama Medical University. In total, 150 patients (mean age, 43.8±21.8 years old) in summer 2012 and 181 patients (mean age, 48.7±18.3 years old) in spring 2013 completed the Self Assessment of Allergic Rhinitis and Asthma (SACRA) questionnaire.

The prevalence of allergic rhinitis in BA patients was 50% in the summer of 2012 and 85.6% in the spring of 2013, indicating a significant seasonal variation. Control of asthma was significantly poorer in both seasons in patients with rhinitis compared to those without rhinitis. Furthermore, in patients with moderate/severe-persistent rhinitis, control of asthma was significantly worse than in patients with mild-intermittent rhinitis in spring 2013, but not in summer 2012.

Although the comorbidity rate of rhinitis among BA patients was greater in the spring than in the summer, rhinitis is thought to be closely related with asthma control regardless of the season.