Key Takeaways

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disorder of excessive inflammation. It should be suspected in patients who present with fever, cytopenias, and evidence of multiple organ involvement.

No clinical, laboratory, or histopathologic finding alone is pathognomonic for the diagnosis of HLH.

HLH is either primary (caused by genetic mutations in NK or T cell function) or secondary (driven by infection, malignancy, or autoimmune disease).

The work-up of HLH should include identifying complications of systemic inflammation as well as a search for a underlying trigger/cause.

The hallmark of HLH treatment is immunosuppression with corticosteroids and etoposide. Additional treatment should be directed at the underlying cause, if isolated.