The Gut Microbiome in the IgE-Mediated Food-Allergic Patient—A Narrative Review

Food allergies (FA) are a major public health concern in both children and adults. Immunoglobulin E (IgE)-mediated FA is characterized by allergic reactions driven by allergen-specific IgE and the subsequent degranulation of mast cells and basophils. Current FA management primarily involves avoidance of allergen-containing food, and more recently, therapies such as oral immunotherapy (OIT), sublingual immunotherapy (SLIT), and the anti-IgE biologic omalizumab. However, these interventions are not curative. The gut microbiome has been implicated in the development and regulation of oral tolerance to food antigens. This narrative review explores the role of probiotics, fecal microbiota transplantation (FMT), dietary interventions, and the interaction between the microbiome and OIT as potential strategies to manage established FA. We also explore barriers to their proliferation as part of regular clinical care. We conclude that future research should (1) address how the microbiome interacts with immunotherapies other than OIT, (2) explore the role of novel microbiome-based treatments like FMT as potential adjuvants to existing food allergy therapeutics, and (3) focus on developing standardized protocols and endpoints for microbiome-based therapeutics.