Is IBS a Food Allergy? Confocal Laser Endomicroscopy Findings in Patients with IBS: A Narrative Review

Irritable bowel syndrome (IBS) is a gut–brain interaction disorder often associated with food-related triggers, yet the efficacy of common exclusion diets remains debated. Confocal laser endomicroscopy (CLE) offers real-time, high-resolution imaging of intestinal mucosal changes, allowing the visualization of food-induced barrier dysfunction. Early evidence indicates that a substantial subset of IBS patients exhibit acute mucosal reactions to specific foods, identified as fluorescein leakage and cell shedding on CLE, with over 70% showing symptom improvements after tailored exclusion diets. These findings suggest that localized immune responses and barrier defects may contribute to IBS symptoms beyond IgE-driven immunologic mechanisms. However, most CLE-based studies are small, unblinded, and heterogeneous, limiting definitive conclusions. Further research is needed to validate the diagnostic accuracy of CLE, refine protocols, and clarify how best to integrate CLE into personalized dietary management for difficult-to-treat IBS.