Hemophagocytic lymphohistiocytosis involves a spectrum of different conditions that have a common pathophysiology of occurrence, which is a strong and unregulated inflammatory response to the antigen. Pathophysiology of HLH syndrome is a regulation disorder of normal physiological immune events with the absence of "down-regulation". It occurs in children and adults. It can be divided into primary and secondary HLH. Secondary HLH is triggered by infections, malignancies, rheumatic diseases and immunomodulatory conditions as associated with the administration of chemotherapeutics and immunosuppressants. The most common icause of infection is the Epstein Barr virus. The clinical picture is usually nonspecific. The initial symptoms can resemble infectious diseases, a prolonged fever of unknown origin, hepatitis, encephalitis, various vasculitis, and several other conditions. Early detection of this condition is crucial for a positive outcome because patients' clinical picture can easily and rapidly deteriorate rapidly resulting in multiorgan failure and death. The diagnosis is based on clinical criteria without any pathognomonic laboratory test or clinical finding. Although the 2004 HLH criteria are still the most common for defining and diagnosing the syndrome, there are some limitations, especially in adult patients. HLH treatment depends on the underlying cause, stage of the disease and, if apparent, its trigger/s . The main goals involve suppressing inflammation, and controlling, reducing and eliminating all identified triggers. Primary HLH is still being treated following the 2004 HLH guidelines, with etoposide and dexamethasone as a bridge to hematopoietic stem cell transplantation. There are still no well-defined guidelines for secondary HLH, but the key is to identify and eliminate the disease’s trigger.