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.

Background There is substantial interest in allergen-specific immunotherapy in food allergy. We systematically reviewed its efficacy and safety. Methods We searched six bibliographic databases from 1946 to 30 April 2021 for randomised controlled trials about immunotherapy alone or with biologicals in IgE-mediated food allergy confirmed by oral food challenge. We pooled the data using random-effects meta-analysis. Results We included 36 trials with 2,126 participants, mainly children. Oral immunotherapy increased tolerance whilst on therapy for peanut (RR 9.9, 95% CI 4.5. to 21.4, high certainty); cow’s milk (RR 5.7, 1.9 to 16.7, moderate certainty) and hen’s egg allergy (RR 8.9, 4.4 to 18, moderate certainty). The number needed to treat to increase tolerance to a single dose of 300mg or 1000mg peanut protein was 2. In peanut allergy, oral immunotherapy did not increase adverse reactions (RR 1.1, 1.0 to 1.2, low certainty) or severe reactions (RR 1,6, 0.7 to 3.5, low certainty). It may increase adverse reactions in cow’s milk (RR 3.9, 2.1 to 7.5, low certainty) and hen’s egg allergy (RR 7.0, 2.4 to 19.8, moderate certainty), but reactions tended to be mild and gastrointestinal. Epicutaneous immunotherapy increased tolerance whilst on therapy for peanut (RR 2.6, 1.8 to 3.8, moderate certainty). Results were unclear for other allergies and administration routes. Conclusions Oral immunotherapy improves tolerance whilst on therapy and is probably safe in peanut, cow’s milk and hen’s egg allergy. However, our review found little about whether this improves quality of life, is sustained or cost-effective.