Eosinophilic gastroenteritis in a patient with chronic hepatitis C who received treatment with pegylated interferon

A 54-year-old male was treated for chronic hepatitis C with pegylated interferon (PEG-IFN) α-2a administered for 24 weeks. HCV-RNA was negative at 24 weeks after treatment, showing sustained virological response (SVR). Abdominal distention and diarrhea were observed 28 weeks after commencing the treatment, i.e., 4 weeks after completing treatment. The elevation of eosinophil count was observed in blood tests and ascites, and because eosinophilic infiltration was also observed on gastrointestinal histopathology, the patient was diagnosed with eosinophilic enteritis. As the eosinophil count spontaneously improved and abdominal symptoms disappeared, the patient was not treated with steroids. The onset of eosinophilic enteritis during interferon therapy is comparatively rare. In this case, PEG-IFN was considered to be the causative factor. Furthermore, we suggested that subserosal eosinophilic enteritis may have characteristic symptoms in patients having hepatic diseases treated with interferon.