Haemophagocytic lymphohistiocytosis (HLH) is a rare and often fatal syndrome of uncontrolled haemophagocytosis and cytokine overproduction that may be primary, or secondary to malignancy, infection, and autoimmunity. There are six previously reported cases linking acute pancreatitis and HLH, but this is the first of necrotising pancreatitis. In this case report, we describe a rare case of HLH associated with necrotising pancreatitis and abdominal compartment syndrome. It highlights the diagnostic uncertainty of HLH particularly given overlapping features seen in sepsis, the use of validated scoring symptoms, associated surgical challenges, and multidisciplinary approaches in treatment. Ultimately, emphasising the need for high degree of suspicion for diagnosis of HLH in surgical patients with persistent fevers and unexplained cytopaenia, the complexity of managing the sequalae of HLH, and the importance of early treatment.