Familial HLH occurs in:
(1) X-linked lymphoproliferative syndrome type 1 (XLP1) = SH2 domain containing 1A (SH2D1A)
(2) X-linked lymphoproliferative syndrome type 2 (XLP2) = X-linked inhibitor of apoptosis (XIAP)
Secondary causes of HLH may be associated with:
(1) infections
(2) autoimmune disorders
(3) malignancies
Bacterial and rickettsial infections:
(1) Anaplasma phagocytophilum
(2) Bartonella
(3) Borrelia
(4) Brucella
(5) Campylobacter
(6) Capnocytophaga
(7) Coxiella burnetti
(8) Ehrlichia
(9) Leptospira
(10) Listeria
(11) Mycobacterium avium-intracellular complex
(12) Orientia tsutsugamushi
(13) Rickettsia
(14) Salmonella
Viral infections
(1) Crimean-Congo hemorrhagic fever
(2) Hantavirus
(3) Hepatitis E
(4) HIV in setting of immune reconstitution inflammatory syndrome or opportunistic infection
(5) infectious mononucleosis (Epstein-Barr Virus, EBV)
(6) influenza (avian influenza H5N1)
(7) rotavirus
(8) SARS coronavirus
Fungi:
(1) Cryptococcus neoformans
(2) Histoplasma capsulatum
(3) Penicillium marneffei
Parasitic infections:
(1) Babesia
(2) Leishmania
(3) Toxoplasma gondii
Autoimmune disorders:
(1) systemic juvenile idiopathic arthritis (SJIA) = Macrophage Activation Syndrome (MAS)
Malignancies:
(1) Hodgkin's disease
