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 produced in excess, they cause damage to the skin, bone, and other parts of the body. In the past, Langerhans cell histiocytosis has been referred to as dendritic cell histiocytosis, histiocytosis X, Hand-Schüller-Christian disease, and Letterer-Siwe disease.
The cause of Langerhans cell histiocytosis is not well understood. It most often affects children between the ages of five and ten, with about one in 200,000 children under ten affected yearly, and only one in 560,000 adults. Caucasians are more likely to exhibit the disease, and males are twice as likely to be affected as females.
Langerhans cell histiocytosis can be divided into three subtypes: unifocal, multifocal unisystem, and multifocal multisystem. The unifocal form, sometimes called by the now obsolete term eosinophilic granuloma, is a slowly progressing disease in which Langerhans cells proliferate in one area of the body, such as the bones, skin, lungs, or stomach. The multifocal unisystem form of the disease causes fever, bone lesions, eruptions 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 unisystem LCH. In multifocal multisystem LCH, Langerhans cells rapidly proliferate in many body tissues, and prognosis is very poor, with a 50% survival rate over five years.
Symptoms of Langerhans cell histiocytosis depend upon 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 painful bone swelling and lesions. If the bone marrow is affected, blood cell deficiency can result. Langerhans cell proliferation in the skin causes a rash, leading to lesions and eruptions, 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 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 typically have an excellent prognosis. Other forms of the disease are usually treated with chemotherapy and steroids. Topical steroid creams may be used for skin lesions, and medication or supplementation can address endocrine deficiency.