A Case of Pyrexia of Unknown Origin Diagnosed as Hemophagocytic Lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is a rare disease that is even rarer in the adult population. It requires a high degree of suspicion from the treating physician, and if diagnosed early, patients might have a survival benefit from this highly fatal condition. HLH is a disorder of immune regulation where the hyperactivity of cytokines attacks different cells, which leads to multiple organ dysfunctions.