Gut eosinophilia in food allergy and systemic and autoimmune diseases.

Eosinophilic gastroenteritis is a rare disease characterized by striking tissue eosinophilia in any layer of the gut wall; however, many diseases can cause increased gut eosinophilia. Allergic reactions to food are an important cause of gut eosinophilia. Not all adverse reactions to food are IgE mediated, and most cases of IgE-mediated food allergy do not have eosinophilic gastroenteritis. Parasitic, bacterial, and viral pathogens as well as certain systemic diseases such as vasculitis can cause gut eosinophilia. These heterogeneous conditions are reviewed in this article.