Common and Disparate Clinical Presentations and Mechanisms in Different Eosinophilic Gastrointestinal Diseases.

Eosinophilic gastrointestinal diseases (EGIDs) are a group of diseases characterized by selective eosinophil infiltration of the gastrointestinal tract in the absence of other causes of eosinophilia. These diseases are generally driven by type 2 inflammation often in response to food allergen exposure. Common among all EGIDs is a clinical presentation characterized by a history of atopic disease with a variety of gastrointestinal symptoms. EGIDs are traditionally separated into eosinophilic esophagitis (EoE) and non-EoE EGIDs. EoE is relatively better understood and now associated with clinical guidelines and a FDA-approved treatment, whereas non-EoE EGIDs are rarer and less well-understood diseases without FDA-approved treatments. Non-EoE EGIDs are further subclassified by the area of the gastrointestinal tract that is involved and comprise eosinophilic gastritis (EoG), eosinophilic enteritis (EoN, includes eosinophilic duodenitis (EoD)), and eosinophilic colitis (EoC). As with other gastrointestinal disorders, the disease presentations and mechanisms differ depending on the involved segment of the gastrointestinal tract; however, the differences between EoE and non-EoE EGIDs extend beyond which GI tract segment is involved. The aim of this article is to summarize the commonalities and differences between the clinical presentations and disease mechanisms for EoE and non-EoE EGIDs.