On the X − 12^th day, a man in his 60s became aware of itching throughout his body. Thus, he visited a dermatologist on the X − 10^th day and was prescribed epinastine hydrochloride and diflucortolone valerate cream. Further, on the X − 8^th day, he visited an internal medicine clinic, and the following findings were noted: aspartate aminotransferase level, 217 U/L; alanine transaminase level, 400 U/L; and immunoglobulin A-hepatitis E virus antibody (IgA-HEV antibody) negative. On the X − 1^st day, he visited the clinic again, and liver damage exacerbation was confirmed. Furthermore, on the X day, he was referred to our hospital. At the time of admission, IgA-HEV antibody was not tested; however, on the X+7^th day, it was found to be positive. Although the examination of the conserved serum revealed that the IgG-HEV antibody, IgM-HEV antibody, IgA-HEV antibody, and HEV-RNA were negative, negative, negative, and positive (subgenotype 4c), respectively, all of them were positive on the X+2^nd day. In rare cases, IgA-HEV antibody may remain negative in the early stage of acute hepatitis E. Thus, IgA-HEV antibody retesting and HEV-RNA testing should be performed if no other condition is suspected and the patient presents with a history of consuming a particular diet, such as meat.

An 85-year-old man with fever, cough, and elevated liver enzymes levels was referred to our hospital. Abdominal echocardiography revealed a thrombus in the hepatic artery and acute liver injury due to ischemia of the hepatic artery. The patient's blood pressure dropped on day 7 after admission, and contrast-enhanced computed tomography revealed a hematoma around the liver, multiple hepatic aneurysms, and a hyperabsorptive zone around the right hepatic aneurysm, leading to the diagnosis of intraperitoneal bleeding due to ruptured hepatic aneurysm. On the 30th day, he presented with hemoptysis, and his respiratory condition worsened; accordingly, antineutrophil cytoplasmic antibody-associated vasculitis was diagnosed based on alveolar hemorrhage and ground-glass appearance on computed tomography. The patient's symptoms improved after steroid pulse therapy and he was discharged. This case indicates that antibody-associated vasculitis rarely causes hepatic aneurysms and should be treated with caution.

A woman in her late teens was being treated with prednisolone and azathioprine for autoimmune demyelinated disorder when she developed drug erythema 2 weeks before admission. Her skin symptoms improved after the drug was discontinued; however, she developed fever and nausea within a week. Laboratory tests revealed that her liver enzymes were elevated, and she was admitted to our department for acute liver injury. Serological tests revealed no evidence of viral hepatitis, and drug-induced liver damage was suspected. On the 8^th hospital day, she developed hepatic encephalopathy with a PT-INR of 2.32. Steroid pulse therapy and continuous hemodiafiltration were initiated for acute liver failure (ALF) and she was placed on the waiting list for liver transplantation. Despite intensive treatment, she developed irreversible brain edema on the 10^th hospital day. We later discovered that serum EBV-DNA (3.3 LogIU/mL) was positive. EBV infection is a rare but severe cause of ALF in adults. Thus, EBV reactivation should be considered in the differential diagnosis of ALF from an unknown cause.