Fibrosing cholestatic hepatitis (FCH) is a severe variant of hepatitis B infection that has until recently been described almost exclusively in the setting of organ transplantation and HIV infection. This case report describes a patient with pre-surface (pre-S) mutant hepatitis B virus (HBV) infection who developed a fatal form of FCH after high dose prednisolone for mixed connective tissue disease (MCTD). The role of corticosteroids and pre-S viral mutation in the pathogenesis of the disease is discussed, and the importance of early diagnosis is emphasised. This report alerts the physician to the need for close monitoring of LFTs and HBV DNA of hepatitis B carriers during immunosuppressive therapy regardless of the indication. As in the transplantation setting, viral DNA levels should be kept to undetectable if viral replication or recurrence is to be prevented.