Abstract
BackgroundExhaled nitric oxide (FeNO) is a well described marker of airway inflammation in asthma and is also known to increase after chronic exposure to inhaled allergens. It is not known whether monitoring FeNO could be useful during food challenges to detect early or subclinical reactions.MethodsForty children aged 3 to 16 years undergoing an allergen-food challenge at two centres were prospectively recruited for this study. FeNO was assessed before and repeatedly after the food-challenge.ResultsData were obtained from a total of 53 challenges (16 positive, 37 negative) and were compared between the two groups. Half of the patients with a positive food challenge exhibited clinical upper respiratory symptoms. The FeNO significantly decreased in 7 of 16 patients with a positive challenge test within 60 to 90 minutes after the first symptoms of an allergic reaction.ConclusionOur results show a significant decrease in FeNO after a positive food challenge suggesting involvement of the lower airways despite absence of clinical and functional changes of lower airways. Prospective blinded studies are needed to confirm these results.
Highlights
The current prevalence of food allergy in childhood varies between 6-8% during the first 3 years of life [1]
There is in agreement with the observation that fractional exhaled nitric oxide (FeNO) reflects bronchial allergic inflammation, and the measurement of FeNO
No challenge was performed the same day after a positive food challenge
Summary
The current prevalence of food allergy in childhood varies between 6-8% during the first 3 years of life [1]. It has been observed that up to 40% of children and adolescents with food allergy but without asthma have concomitant asymptomatic bronchial hyperreactivity (BHR) to methacholine, in general without lung function changes [2,3]. It has been shown earlier that FeNO increases after specific bronchial allergen provocation in adults [7], whereas no changes in FeNO have been reported after a nasal allergen challenge in children [8]. Exhaled nitric oxide (FeNO) is a well described marker of airway inflammation in asthma and is known to increase after chronic exposure to inhaled allergens. It is not known whether monitoring FeNO could be useful during food challenges to detect early or subclinical reactions
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