Azathioprine-Induced Eosinophilia and Acute Cholestatic Hepatitis in Lupus Nephritis: An Early Hypersensitivity-Mediated Presentation of Thiopurine-Associated Drug-Induced Liver Injury.

Azathioprine is a thiopurine immunosuppressive medication widely used in the treatment of autoimmune diseases and organ transplantation. Although hematologic toxicity is well recognized, hepatotoxicity and hypersensitivity reactions are less commonly encountered but clinically significant adverse effects. We present the case of a 20-year-old female with systemic lupus erythematosus and class III lupus nephritis who developed progressive nausea, fatigue, eosinophilia, pancytopenia, and marked transaminase elevation shortly after initiation of azathioprine therapy. Imaging excluded biliary obstruction, while endoscopic and histologic evaluation demonstrated inflammatory changes with eosinophilic infiltration. Liver biopsy confirmed acute intrahepatocellular cholestatic hepatitis. Discontinuation of azathioprine led to rapid biochemical improvement and resolution of eosinophilia. This case highlights an early hypersensitivity-mediated presentation of azathioprine-induced liver injury and underscores the importance of early recognition and prompt drug withdrawal.