Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is an important cause of multi-organ dysfunction and can mimic other disorders including sepsis. We describe a patient presenting with septic shock and accompanying high procalcitonin. Although initially treated empirically with antibiotics, the emergence of eosinophilia during the admission lead to a revised diagnosis of DRESS syndrome, presumed secondary to acetazolamide. This case highlights the importance of regular clinical assessment and re-evaluation is key in identifying emerging features such as eosinophilia, rash and organ dysfunction, which can secure the diagnosis. Furthermore, the case also highlights that acetazolamide may be a rare cause of DRESS syndrome.