Eosinophilic colitis: clinical review and 2020 update

Eosinophilic colitis (EC) is a rare inflammatory disease included in the chapter of eosinophilic gastrointestinal disorders (EGIDs), diagnosed by the presence of primary eosinophilic infiltrate in the colon wall in symptomatic patients. While the etiology of primary colonic eosinophilia is unknown, several conditions are involved in the pathogenesis of secondary eosinophilic colonic infiltrate (food allergens, parasitic infections, drugs), which have to be excluded in order to correctly diagnose the primary form of the disease. Up to now, EC is lacking of codified guidelines regarding diagnostic criteria (especially eosinophil threshold values) and treatment, thus a correct approach to EC remains very challenging. Imaging, laboratory tests and endoscopy might be helpful in ruling out other mimic conditions, but EC is still a diagnosis of exclusion. Several treatment options are feasible, but most of the evidences are drawn from case reports and small case series, thus limiting their value. We carried out a review of the current literature to evaluate the more appropriate and modern clinical strategy for diagnosis and management of EC.