Langerhans cell histiocytosis (LCH) is a rare disease in which Langerhans cells proliferate abnormally. Langerhans cells are part of the immune system, normally found in the skin and lymph nodes. When the cells are overproduced, they cause damage to the skin, bones, and other parts of the body. In the past, Langerhans cell histiocytosis was called dendritic cell histiocytosis, histiocytosis X, Hand-Schüller-Christian disease, and Letterer-Siwe disease.
The cause of Langerhans cell histiocytosis is not well understood. It often affects children between the ages of five and ten, with about one in 200,000 children under the age of ten affected annually, and only one in 560,000 adults. Caucasians are more likely to have the disease, and men are twice as likely to be affected as women.
Langerhans cell histiocytosis can be divided into three subtypes: unifocal, unisystem multifocal, and multisystem multifocal. The unifocal form, sometimes called by the obsolete term eosinophilic granuloma , is a slowly progressive disease in which Langerhans cells proliferate in one area of the body, such as the bones, skin, lungs, or stomach. The multifocal, unsystemic form of the disease causes fever, bone lesions, rashes on the scalp and in the ear canals, and bulging eyes. Diabetes insipidus, a condition characterized by excessive thirst and urination, occurs in 50% of multifocal unsystemic LCH. In multifocal multisystem LCH, Langerhans cells proliferate rapidly in many body tissues, and the prognosis is very poor, with a 50% survival rate over five years.
The symptoms of Langerhans cell histiocytosis depend on the form of the disease and the tissues affected. Anemia, fever, lethargy, and weight loss are common. If the bones are affected, symptoms can include swelling and painful bone lesions. If the bone marrow is affected, it can lead to a deficiency of blood cells. The proliferation of Langerhans cells in the skin causes a skin rash that leads to lesions and rashes, particularly on the scalp.
If Langerhans cell histiocytosis affects the endocrine glands, diabetes insipidus and permanent anterior pituitary hormone deficiency are likely symptoms. The lymph nodes, spleen, and liver can become enlarged if they are affected by the disease. In Langerhans cell histiocytosis is present in the lungs, the patient may experience shortness of breath or chronic cough.
Langerhans cell histiocytosis is diagnosed by tissue biopsy. Limited unifocal cases can often be treated with local radiation or surgery and generally have an excellent prognosis. Other forms of the disease are usually treated with chemotherapy and steroids. Topical steroid creams can be used for skin lesions, and medications or supplements can address endocrine deficiency.