Exhaled Nitric Oxide and Symptom Severity in Children with Allergic Rhinitis

Objective: There have been few reliable biomarkers to evaluate allergic rhinitis (AR) severity in children. This study aimed to investigate a biomarker for assessing AR severity in children. Methods: A total of 107 children with AR (80) and non-allergic rhinitis (NAR, 27) were included in this study. The fraction of exhaled nitric oxide (FeNO) was measured and AR severity and duration was graded in patients with AR. We assessed the association between FeNO and the Allergic Rhinitis and its Impact on Asthma (ARIA) classes. Results: FeNO levels in the AR and NAR groups were 34.7 ± 22.1 and 17.0 ± 13.1 ppb, respectively (p=0.001). FeNO levels were significantly different (p<0.05) in the four ARIA classes: 14.3 ± 3.7 ppb in the mild intermittent group, 22.7 ± 4.8 ppb in the mild persistent group, 32.1 ± 16.1 ppb in the moderate-to-severe intermittent group, and 48.2 ± 25.2 ppb in the moderate-to-severe persistent group. We collapsed the 4 ARIA classes into 2 groups based on severity or duration. FeNO levels of the mild symptom group and moderate-to-severe symptom group were 18.7 ± 6.0 and 41.1 ± 23.0 ppb, respectively, which were significantly different (p=0.001). FeNO levels of the intermittent duration group (n=36) and persistent duration group (n=44) were 26.6 ± 15.9 and 41.2 ± 24.4 ppb, respectively, which were significantly different (p=0.001). Conclusion: FeNO levels were higher in children with increased severity and duration of AR. FeNO could be an indicator for classifying severity and evaluating treatment efficacy in children with AR.