[2][3] Presentation may vary depending on location as well as depth and extent of bowel wall involvement and usually runs a chronic relapsing course.

Approximately 80% have symptoms for several years;[7] a high degree of clinical suspicion is often required to establish the diagnosis, as the disease is extremely rare.

[15] As a part of host defense mechanism, eosinophils are normally present in gastrointestinal mucosa, though the finding in deeper tissue is almost always pathologic.

[17] In addition eotaxin has been shown to have an integral role in regulating the homing of eosinophils into the lamina propria of stomach and small intestine.

[18] In the allergic subtype of disease, it is thought that food allergens cross the intestinal mucosa and trigger an inflammatory response that includes mast cell degranulation and recruitment of eosinophils.

CT scans may show nodular and irregular thickening of the folds in the distal stomach and proximal small bowel, but these findings can also be present in other conditions like Crohn's disease and lymphoma.

[citation needed] The endoscopic appearance in eosinophilic gastroenteritis is nonspecific; it includes erythematous, friable, nodular, and occasional ulcerative changes.

Various steroid sparing agents e.g. sodium cromoglycate (a stabilizer of mast cell membranes), ketotifen (an antihistamine), and montelukast (a selective, competitive leukotriene receptor antagonist) have been proposed, centering on an allergic hypothesis, with mixed results.