Eosinophilic esophagitis (EoE) is a chronic immune disorder characterized by a mix of IgE and non-IgE mediated hypersensitivity in response to an allergen (most often, food).

Innate and adaptive mechanisms play a role in the pathogenesis of EoE. Th-2 cell activation after exposure to an offending agent result in a cascade of inflammatory cells (i.e., mast cells, basophils, and dendritic cells). These cells produce and release eosinophils, basophils, histamine, and interleukins (IL)-4, 5, 9 and 13, leading to an acute eosinophilic based allergic response with mucosal infiltration and edema. Fibrosis and dysmotility from chronic inflammation result in stricture formation, luminal narrowing, and esophageal ring formation.