Life threatening rickettsiosis and the role of hemophagocytic lymphohistiocytosis syndrome (HLH): Case report of a 21-year-old woman.

Hemophagocytic lymphohistiocytosis (HLH) syndrome is an uncontrolled activation of macrophages, causing multiorgan dysfunction. The prognosis depends on the cause and the delay of diagnosis and treatment. Several infections can cause HLH, including rickettsia, a gram-negative bacterium.