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

PurposeFractional 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.MethodsA 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.ResultsChildren 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%.ConclusionFnNO, FeNO, and pulmonary function tests may help assess disease severity and level of disease control in children with persistent AR.