Eosinophilic gastrointestinal diseases (EGIDs) are characterized by GI signs or symptoms occurring along with tissue eosinophilia. Eosinophilic esophagitis (EoE) is the more commonly recognized EGID as endoscopic and histopathologic diagnostic criteria have long been established. Because of a lack of consensus on biopsy protocols, poorly understood histopathologic diagnostic criteria, and vague, nonspecific gastrointestinal complaints, patients with non-EoE EGIDs go unrecognized for years. Because of this, there is increasing emphasis on better defining rare, distal eosinophilic gastrointestinal diseases (i.e., eosinophilic gastritis, enteritis, and colitis).
EGID nomenclature was standardized in 2022 in part to minimize vague terminology (i.e., eosinophilic gastroenteritis) and to provide more specific information about the location of eosinophilic disease. The 2022 nomenclature suggest that EGID be used as the umbrella term for all GI luminal eosinophilia (without a known cause) but with emphasis on the site of specific eosinophilic involvement (i.e., eosinophilic gastritis or eosinophilic gastritis and colitis). Importantly, there is much work to be done to adequately identify patients suffering from EGIDs. Symptoms are variable, ranging from abdominal pain, bloating, and nausea seen in proximal disease to loose stools and hematochezia in more distal involvement. Signs of disease, such as iron or other nutrient deficiencies and protein loss, may also occur. Endoscopic findings can vary from erythema, granularity, erosions, ulcerations, and blunting to even normal-appearing tissue. In eosinophilic gastritis, Ikuo Hirano, MD, and colleagues demonstrated that increasing endoscopic inflammatory findings in the stomach correlate with assessment of disease severity. Regardless of endoscopic findings, numerous biopsies are needed for the diagnosis of EGIDs because, as already established in EoE, eosinophil involvement is patchy. Nirmala Gonsalves, MD, and Evan Dellon, MD, found that a minimum of four biopsies each in the gastric antrum, gastric body, and small bowel are needed to detect disease. Optimal biopsy patterns have not yet been determined for eosinophilic ileitis or colitis.
Despite these advances, there is more work to be performed. Although these disease states are termed “eosinophilic,” the immunopathology driving these diseases is multifactorial, involving lymphocytes and mast cells and creating different phenotypes of disease in a similar fashion to inflammatory bowel disease. Current therapies being studied include eosinophil-depleting medications along with others targeting T2 immune pathways. Patients may need multiple therapeutic options, and personalized medicine will soon play a larger role in defining treatments. For now, researchers are fervently working on improved methods to identify, phenotype, and treat these morbid disorders.
Dr. Peterson is associate professor of gastroenterology at University of Utah Health, Salt Lake City. She has no relevant conflicts of interest. These remarks were made during one of the AGA Postgraduate Course sessions held at DDW 2022.