Evaluation of Fractional Exhaled Nitric Oxide in Pediatric Asthma and Allergic Rhinitis

Abstract

Fractional exhaled nitric oxide (FeNO) is a non-invasive test for evaluating the degree of airway inflammation and for the diagnosis, evaluation, and treatment of asthma. We attempted to measure FeNO levels in Korean children with asthma and determine its cutoff value for diagnosing asthma. We enrolled 176 children and adolescents between the ages of 5 and 18 years, who visited for the evaluation of chronic cough, shortness of breath, and wheezing. Among them, 138 patients who underwent skin prick tests or inhalation Immuno CAP (UniCAP; Pharmacia, Uppsala, Sweden) tests for allergy testing together with a pulmonary function test were included. FeNO was measured using a NIOX MINO (Aerocrine AB, Solna, Sweden) instrument according to the American Thoracic Society/European Respiratory Society (ATS/ERS) guidelines. There were 29 patients with asthma, 43 with rhinitis, and 38 with asthma and allergic rhinitis. In the asthma group, FeNO levels significantly correlated with total immunoglobulin E (r = 0.572, p < 0.001), but did not show significant correlation with pulmonary function test parameters (forced vital capacity—FVC, forced expiratory volume in one second—FEV1, FEV1/FVC) or PC20 (provocative concentration of methacholine causing a 20% fall in FEV1). The FeNO cutoff values obtained in the asthma and asthma rhinitis groups were 16.5 ppb and 18.5 ppb, respectively. Hence, we provide a FeNO cutoff value according to the presence or absence of rhinitis in pediatric patients with asthma.

International consensus statement on allergy and rhinology: Allergic rhinitis – 2023

“…FeNO is primarily utilized in the diagnosis and monitoring of therapeutic response and compliance in asthma, 1644–1647 but recent research has attempted to expand this testing for diagnosis of AR. Small studies have shown increased FeNO in AR patients, especially those with concomitant asthma 1648–1651 . This finding was also seen in a large population study from The Netherlands which showed independent association of elevated FeNO in patients with positive skin testing, eczema, or AR 1643 (Table X.G.‐1).…”

Development of sensitization to peanut and storage proteins and relation to markers of airway and systemic inflammation: A 24‐year follow‐up

“…Fractional exhaled nitric oxide (FENO) is a biomarker mainly associated with respiratory inflammation. 17 It can be measured by a simple non‐invasive test and is mainly used for evaluating the degree of airway inflammation. FENO is driven by the activation of the Th2 pathway 18 and elevated levels are often found in patients with untreated type 2 inflammation in bronchi and bronchioles, comorbid nasal polyposis, airborne allergy and in patients with an airborne allergy such as to furry animals, house dust mites and pollen 14 , 19 , 20 , 21 and food allergens.…”

“…Fractional exhaled nitric oxide (FENO) is a biomarker mainly associated with respiratory inflammation 17 . It can be measured by a simple non‐invasive test and is mainly used for evaluating the degree of airway inflammation.…”

Screening Accuracy of FeNO Measurement for Childhood Asthma in a Community Setting

“…The published evidence concerning the diagnostic value of the FeNO measurement in asthma is more convincing from a clinical point of view and supports the use of the test in predicting asthma [ 8 ]. The screening performance of the test in a community setting was addressed by a small number of studies and the results are unequivocal [ 9 , 10 , 11 ].…”