In this disease, Langerhans Cells grow abnormally due to changes that are not currently well understood. Patients exhibit symptoms related to accumulation of these cells in different parts of the body, including the bones, lungs, bone marrow, lymph nodes, skin, liver and brain. Why some individuals develop LCH remains unknown.

Because histiocytosis may involve a variety of different organs in the body, children with this disease experience a spectrum of symptoms, which may include bone pain, rash, shortness of breath, fever, fatigue, and excessive thirst and urination. The symptoms of LCH generally occur gradually and, at times, may resolve without any treatment. However, in certain cases the disease can be life-threatening.

Due to the rare nature of LCH, and until recently, the difficulty in growing Langerhans cells in the laboratory, little was known about the cause of this disease or how best to treat it. Because many questions still remain unanswered, DF/CHCC's Histiocytosis Research Program was established to conduct research aimed at improving the care of patients affected by this disease.