Fraction of Exhaled Nitric Oxide (FeNO) and Abdominal Pain and/or Vomiting in Reaction to Oral Food Challenge
Sunday, March 6, 2016
South Exhibit Hall H (Convention Center)
Sara C. Slatkin, MD, Dana Tupa, Kari C. Nadeau, MD PhD FAAAAI, R. Sharon Chinthrajah, MD

FeNO is a surrogate marker of eosinophilic inflammation. Its clinical role in asthma is well established, as well as its relationship to peripheral, bronchial biopsy, sputum, and BAL eosinophilia. It has yet to be correlated with gastrointestinal eosinophilia and to be fully characterized in food allergy patients. We hypothesized that patients with elevated FeNO are more likely to have abdominal pain and/or vomiting with oral allergen challenge.


The Sean N. Parker Center for Allergy Research at Stanford screened 20 pediatric patients for an oral immunotherapy clinical trial and performed 80 FeNO measurements prior to double-blind placebo-controlled food challenges (DBPCFC). FeNO was obtained according to ATS guidelines, using Niox Mino. Exclusion criteria were: FEV1 less than 80% predicted, nitrate-rich food intake, or respiratory distress before or after challenge. 


FeNO, prior to DBPCFC, predicts abdominal pain and/or vomiting with a specificity of 82% at a cut-off of 60 ppb. Mean FeNO was 52 ppb in patients with abdominal pain and/or vomiting, compared to 41 without. There were no significant differences in gender, age, height, BMI, asthma, allergic rhinitis, atopic dermatitis, FEV1, use of inhaled corticosteroids, nasal steroids, or H2-blockers, and total IgE, as analyzed by Fisher’s exact and the two sample t-tests.


Elevated FeNO was associated with abdominal pain and/or vomiting in DBPCFC, in this pediatric population with food allergies. This result, if confirmed in a larger cohort, will allow use of a non-invasive test for the prediction of GI responses to oral allergen challenge.