Classification of eosinophilic disorders of the small and large intestine.

Eosinophilic gastrointestinal diseases (EGIDs), including eosinophilic gastroenteritis and eosinophilic colitis, have been increasing in prevalence in Western countries in recent years. Eosinophils are normally scanty in the gastrointestinal tract, and increased numbers of eosinophils can denote pathology. Normal values for tissue eosinophils vary widely between different segments of the colon, thus location of the biopsy is critically important for the interpretation of findings. However, no standard diagnostic criteria have been proposed for the diagnosis of eosinophilic gastroenteritis or eosinophilic colitis. Gut eosinophilia encompasses entitites that are predominantly immunoglobulin E (IgE)-mediated, the primary EGIDs and those that are secondary and not IgE-mediated. A final diagnosis of eosinophilic gastrointestinal diseases requires careful pathological assessment, clinical correlation and exclusion of several differential diagnoses.