Eosinophilic Disorders of Childhood

Allergy and eosinophilia in the gastrointestinal (GI) tract are not equivalent. GI eosinophilia is associated with infections (parasites), nutritional deficiencies, inflammatory processes, neoplasias, and systemic disorders. However, in addition to eosinophilia, other histologic changes usually accompany the increased number of eosinophils in most of these conditions. In contrast, there is a group of GI disorders that are primarily or exclusively characterized by tissue eosinophilia in the absence of known causes for eosinophilia. These primary eosinophilic GI disorders include eosinophilic esophagitis (EoE), allergic proctocolitis, and eosinophilic gastroenteritis. Several lines of evidence support an allergic cause for these disorders but in many patients a specific allergen is not easily identified..