Eosinophilic Gastrointestinal Disorders

INTRODUCTION T he eosinophilic gastroenteropathies are an interesting, yet somewhat poorly defined set of disorders that by definition include the infiltration of at least one layer of the gastrointestinal (GI) tract with eosinophils. First reported over 50 years ago, the clinical spectrum of these disorders was defined solely by various case reports. As these reports became more frequent, various aspects of the disease became better described and stratified. Additional insight into the role of the eosinophil in health and disease has allowed further description of these disorders with respect to the underlying defect that drives the inflammatory response in those afflicted (Table 1). Perhaps, most important to the definition has been the understanding of the heterogeneity of the sites affected within the gastrointestinal tract. Within the broad classification of these disorders lie at least three clinical entities that are defined in large part by the presence of abnormal numbers of eosinophils in various GI sites: eosinophilic proctocolitis (EP), eosinophilic gastroenteritis (EG), and eosinophilic esophagitis (EE) (Table 2).