Human rhinoviruses (HRVs) infection is a common cause of exacerbations in pediatric patients with asthma. However, the effects of corticosteroids on HRV-induced exacerbations in pediatric asthma are unknown. We conducted a prospective observational study in inpatients aged 6–16 years with asthma exacerbations to investigate the effects of inhaled corticosteroids (ICS) on the detection rates of HRV species from nasopharyngeal samples and treatment periods of systemic corticosteroids on pulmonary lung function 3 months after exacerbations. Viral pathogens were identified in 45 out of 54 patients (83.3%) using multiplex PCR assay. HRV-A, -B, and -C were detected in 16 (29.6%), one (1.9%), and 16 (29.6%) patients, respectively. The detection rates of HRV-C were lower in the ICS-treated group compared with those in the ICS-untreated group (p = 0.01), whereas maintenance ICS did not affect the detection rate for viral pathogens in total and HRV-A. Changes in forced expiratory volume in one second predicted from baseline in patients treated with systemic corticosteroids for 6–8 days were higher than those in patients treated within 5 days (p = 0.0085). The protective effects of corticosteroids on virus-induced asthma exacerbations may be dependent upon the types of viral pathogen.

Background Viral infection of the respiratory tract, predominantly by human rhinoviruses (HRVs), is a common cause of exacerbations in pediatric patients with asthma. However, the effects of corticosteroids on HRV-induced exacerbations in pediatric asthma are unknown. We conducted a prospective observational study to determine the viral pathogens in school-age pediatric inpatients with asthma exacerbations. We assessed the effects of maintenance inhaled corticosteroids (ICS) on the detection rates of HRV species and treatment periods of systemic corticosteroids during exacerbations on pulmonary lung function 3 months after HRV-induced exacerbations. Methods Nasopharyngeal samples and clinical information were collected from 59 patients with asthma exacerbations between April 2018 and March 2020. Pulmonary function tests were carried out 3 months after exacerbations in 18 HRV-positive patients. Changes in forced expiratory volume in one second (FEV1)% predicted from baseline in a stable state were compared according to the treatment periods of systemic corticosteroids. Results Fifty-four samples collected from hospitalised patients were analysed, and viral pathogens were identified in 45 patients (83.3%) using multiplex PCR assay. HRV-A, -B, and -C were detected in 16 (29.6%), one (1.9%), and 16 (29.6%) patients, respectively. There was no significant difference in the detection rates of viral pathogens in total between patients treated or not treated with maintenance ICS. The detection rates of HRV-C were lower in the ICS-treated group compared with those in the ICS-untreated group (p = 0.01), whereas ICS treatment did not affect the detection rate for HRV-A. Changes in FEV1% predicted in patients treated with systemic corticosteroids for 6–8 days (n = 10; median, 4.90%) were higher than those in patients treated within 5 days (n = 8; median, − 10.25%) (p = 0.0085). Conclusions Maintenance ICS reduced the detection rates of HRV (mainly HRV-C) in school-age inpatients with asthma exacerbations, and the treatment periods of systemic corticosteroids during exacerbations affected lung function after HRV-induced exacerbations. The protective effects of corticosteroids on virus-induced asthma exacerbations may be dependent upon the types of viral pathogen.