The Significance of Fractional Exhaled Nitric Oxide, Fractional Nasal Exhaled Nitric Oxide and Lung Function Tests in Children with Moderate-to-Severe Allergic Rhinitis.

Purpose: Fractional nasal exhaled NO (FnNO), fractional exhaled NO (FeNO) and lung function tests were performed in children with moderate-to-severe persistent allergic rhinitis (AR) to investigate the significance of the above indices in the assessment and diagnosis of children with AR.

Methods: A total of 135 children with persistent AR were selected and divided into moderate-to-severe and mild groups; serum total immunoglobulin E (IgE), peripheral blood eosinophil counts (EOS), FnNO, FeNO, and lung function tests were performed.

Results: Children in the moderate-to-severe group had increased levels of FnNO and FeNO and decreased levels of forced expiratory flow at 75% of forced vital capacity as a percentage of the predicted value (FEF75%) and maximum mid-term expiratory flow as a percentage of the predicted value (MMEF%) . IgE in children with AR was positively correlated with FeNO and FnNO and negatively correlated with FEF75% . EOS was positively correlated with FnNO. FeNO was negatively correlated with FEF75% and forced expiratory flow at 50% of forced vital capacity as a percentage of the predicted value (FEF50%). FnNO was negatively correlated with FEF75%, FEF50%, and MMEF%.

Conclusion: FnNO, FeNO, and pulmonary function tests may help assess disease severity and level of disease control in children with persistent AR.