Haemophagocytic lymphohistiocytosis is characterised by signs and symptoms, like fever, rash, neurological symptoms, hepatosplenomegaly, lymphadenopathy, cytopenias, high serum ferritin, hypertriglyceridaemia and abnormalities of liver function and coagulation. Symptoms occur generally within 4 weeks of treatment initiation. Patients should be informed of the symptoms and advised to seek immediate medical attention if they experience these symptoms. In patients presenting with these symptoms lamotrigine should be discontinued until a diagnosis is established.