Azathioprine (AZA) is used in clinical practice as a steroid-sparing medication to treat diverse systemic autoimmune diseases, such as inflammatory bowel disease, rheumatoid arthritis, and systemic lupus erythematosus. The adverse effects of AZA use include azathioprine hypersensitivity syndrome (AHS). AHS is a rare entity, but it can lead to fatal outcomes if not identified early. Fever and abdominal pain, while resembling other diseases, can be a sign of this disease. This paper discusses the case of a patient diagnosed with systemic lupus erythematosus who experienced AHS.