Introduction Patients with food allergies necessite having personalized information on their risk of reaction in “real-life” situations. This multicentric study aimed to investigate the link during accidental reactions between the nature and amount of food allergens consumed in “real life situation” and the severity of the symptoms. Methods Patients were prospectively recruited from the 1 st of December 2020 to the 31 st of December 2021 at the emergency departments in the Geneva University Hospitals and local pediatric urgent care, trough the allergology outpatient consultation, at school and daycare facilities and trough their primary care physicians. Medical history of patients presenting reactions suggestive with immediate food allergy and suspected food samples were collected. Allergy diagnostic tests were retrospectively and prospectively collected. The samples were analyzed for their allergen content. Results We recruited 147 subjects with an accidental immediate-type allergic reaction to a food. We were able to collect 115 reaction-eliciting food samples allowing to quantify the allergen amount occasioning the reaction, as well as correlating this amount to the severity of the reaction. Children represented a large part of the reactors, and most reactions were to common food allergens such as tree nuts, cow’s milk as well as peanuts and hen’s egg. Reactions were mostly to pre-packaged foods and seven were to products with Precautionary allergy labeling, or without labelling to the corresponding allergen. Reactions were of various degrees of severity, and independent to the amount of allergen ingested. Discussion The severity of reactions did not show a direct correlation with allergen quantity, emphasizing individual sensitivity. Some reactions occurred with allergen amounts significantly below the legal limit for mandatory labelling of 1 g/kg in Switzerland. The study also highlighted considerable variability in allergen concentrations in foods labeled with possible “contaminations” or “traces.” These findings raise questions about the accuracy of allergen labeling and regulations.

Background: Abdominal pain is a frequent symptom of IgE-mediated food allergy with limited therapeutic options. Visceral smooth muscle cell relaxation can be induced by activation of the beta-adrenergic receptors. Objective: To evaluate the efficacy of inhaled salbutamol empirically used to relieve abdominal pain caused by IgE-mediated allergic reactions at one center. Methods: All double-blind placebo-controlled food challenges to peanut performed at CHU Sainte-Justine between 2016 and 2020 were reviewed to identify patients that presented abdominal pain as part of their reaction. The primary outcome measure was the delay between the initiation of therapy and improvement of abdominal pain. It was compared between patients that had received inhaled salbutamol as part of their treatment and those that did not. Linear regression was performed to control for potential confounders. Results: During the study period, 174 positive DBPCFCs were performed, including 116 for peanut allergy. Of these, 77 presented abdominal pain and 49 met the criteria for inclusion in the study. Patients that received salbutamol improved significantly faster (median 14 minutes; range 5-66) than those that did not (61 minutes range 5-194) (p<0.0001). In the linear regression, only the administration of salbutamol and emesis were found to independently accelerate the recovery of abdominal pain, each reducing the time to improvement by an average of 61 ±10 minutes (p<0.0005) and 44 ±13 minutes (p<0.0005), respectively. Conclusion: This retrospective study provides low-quality evidence of a large effect for salbutamol in the treatment of gastro-intestinal anaphylaxis. Further investigation in randomized controlled trials would be warranted.