A Review of Non-IgE Immune-Mediated Allergic Disorders of the Gastrointestinal Tract

Non-IgE immune-mediated gastrointestinal disorders constitute a heterogeneous group of enigmatic conditions that are on the rise. This category encompasses entities like food protein-induced enterocolitis syndrome (FPIES), food protein-induced allergic proctocolitis (FPIAP), and food protein-induced enteropathy (FPE). These are immune-mediated reactions to certain foods without the involvement of allergen-specific IgE in their pathogenesis. Eosinophilic esophagitis (EoE) is also included in this group, acknowledged for its mixed IgE and non-IgE-mediated characteristics. The diagnostic landscape is fraught with challenges, given the poorly understood nature of these disorders and their propensity to manifest with varying and overlapping clinical presentations, typically emerging in infancy with common potential triggers such as cow's milk and soy. Presently, confirmatory testing for most of these conditions is limited and invasive, emphasizing the pivotal role of a thorough history and physical examination in reaching a diagnosis. Notably, there are limited guidelines for diagnosis and management for most of these disorders. This article elucidates the key distinctions among these disorders, provides an overview of existing diagnostic and therapeutic approaches, and addresses existing knowledge and research gaps. The considerable impact on the quality of life of non-IgE immune-mediated allergic disorders of the gastrointestinal tract, which can result in debilitating complications such as nutritional deficiencies, mental health disorders, and eating disorders, underscores the urgency for comprehensive exploration and management strategies.