Hemophagocytic lymphohistiocytosis is a rare immune disorder that primarily affects children and infants, according to Johns Hopkins Medicine. Although children usually inherit the condition, older patients develop HLH in response to cancer, viral infections and other health problems.
HLH causes certain types of white blood cells, called histiocytes and lymphocytes, to attack other blood cells, explains Johns Hopkins Medicine. The abnormal blood cells accumulate in the liver and spleen, causing the organs to become enlarged.
Doctors classify HLH into two types: familial, which is an inherited condition passed down from either parent who is a genetic carrier of the condition, and acquired, which is caused by other health problems, such as cancer, an already weakened immune system and infections, reports Johns Hopkins Medicine. The Epstein-Barr virus is one of the most prevalent causes of acquired HLH.
HLH symptoms include a variety of neurological, pulmonary and digestive problems, states Johns Hopkins Medicine. They include visual disturbances, headaches, trouble walking and difficulty breathing. Patients may also experience an enlarged liver, jaundice, nausea, vomiting and diarrhea. Other symptoms reported are swollen lymph nodes and skin rashes. Babies may develop irritability and failure to thrive.
Familial HLH can be fatal if not treated, warns Johns Hopkins Medicine. Acquired HLH will usually resolve itself once the underlying disease is treated.