Eosinophilic gastrointestinal disorders

ABSTRACT

Eosinophilic gastrointestinal disorders are rare inflammatory diseases of unknown origin defined as disorders that selectively affect the gastrointestinal tract with eosinophil-rich inflammation in the absence of known causes for eosinophilia [eg, drug reactions, parasitic infections, and malignancy]. Eosinophil levels fluctuate, predating presentation by years and may be absent at presentation. Allergic mechanism has been suggested in at least a subset of patients. Indeed, increased total IgE and food-specific IgE levels have been detected in the majority of patients. A majority of patients have positive skin test responses to a variety of food antigens but do not have typical anaphylactic reactions, which is consistent with a delayed-type of food hypersensitivity syndrome. A male preponderance in the third to fifth decades of life has been reported. 25% have a history of atopy. Presentation may vary from a single organ affected by eosinophilic infiltrate to that of multisystem involvement. The gastric antrum and proximal small bowel are the most affected sites, commonly presenting with obstruction. Frank ulceration and haemorrhage are unusual. Symptoms are non-specific with nausea, vomiting, dyspepsia, abdominal pain, and weight loss. Approximately 80% have symptoms for several years before diagnosis. Eosinophilic gastroenteritis can present with protein-losing enteropathy. Serosal inflammation is the most likely cause of the exudative ascites. Biliary obstruction is a rare presentation of eosinophilic gastroenteritis. Presentation can mimic malignancy. Ultrasound, computed tomography and contrast studies may show nonspecific features of thickened mucosa and bowel wall. The histology is characteristic with mucosal oedema, a dense eosinophilic infiltrate, muscle bundle hypertrophy, and fibrosis. The submucosa is most commonly affected and full thickness biopsies may be needed for diagnosis. Treatments are often unsatisfactory, and long-term outcomes are uncertain. Prednisolone 20-40 mg per day remains an empirical treatment. Elimination diets and sodium cromoglycate are successful in rare cases where the causative antigen is isolated. Drugs such as montelukast, ketotifen, suplatast tosilate, mycophenolate mofetil, and alternative Chinese medicines have been advocated but are generally not successful. Spontaneous resolution may occur. It is hoped that a better understanding of the pathogenesis and treatment of EG will emerge by combining holistic clinical and research approaches involving experts in the fields of allergy, gastroenterology, nutrition, and pathology