[A case of eosinophilic esophagogastroenteritis which developed after rush oral immunotherapy for egg allergy].

Rush oral immunotherapy was provided to a 9 year old boy suffering from egg allergy. The patient reached the goal of one boiled egg daily on day 22 of treatment. He was discharged from the hospital the following day, with the maintenance dose of one whole egg to be taken daily. However, the patient began to experience abdominal pain and vomiting after ingestion of egg approximately one day after discharge. Blood tests revealed a remarkable increase in eosinophils in peripheral blood, and we reduced the patient's intake of egg. The patient's condition did not improve, and he gradually started to lose weight. Maintenance dosing was stopped completely on day 38. An endoscopic biopsy of the mucosa lining from the esophagus to the duodenum was performed on day 45. The results confirmed prominent diffuse eosinophilic infiltration of the entire upper gastrointestinal tract. The patient was finally diagnosed with eosinophil esophagogastroenteritis. While this condition is rare, it should be considered in future cases of persistent gastrointestinal symptoms during food allergy immunotherapy.