Eosinophilic gastritis is a rare disease of unknown etiology, characterized by inflammation of the gastric wall with eosinophilic infiltration and peripheral blood eosinophilia. It is not associated with granulomas or vasculitic lesions. Although all layers of the gastric wall can be affected, the disease typically predominates in one specific layer. Gastric mucosal biopsy plays a crucial role in diagnosis, revealing marked eosinophilic infiltration, which may even form eosinophilic microabscesses, necrosis with neutrophilic infiltration, and epithelial regeneration. However, when the lesions are confined to the muscular or subserosal layers, diagnosis through mucosal biopsy may be challenging. The extent of the lesions may involve both the stomach and small intestine or remain localized to the stomach. This condition is thought to result from an antigen-antibody reaction occurring in the gastrointestinal wall following exposure of gastrointestinal tissues to allergens, leading to the release of histamine-like vasoactive substances.
Clinical manifestations include epigastric pain, nausea, vomiting, and diarrhea, with abdominal pain being refractory to acid-suppressive agents. Peripheral blood eosinophilia is commonly observed. The disease is often self-limiting, but some patients may experience persistent or recurrent symptoms. Treatment with glucocorticoids can be effective.