Langerhans cell histiocytosis (LCH) is more common in children, but it can also occur in adults. Most frequently, LCH is a mild illness affecting the skin or only a few bones. However, some people with LCH have tumors in many organs. LCH of the skin can cause a variety of rashlike conditions. These disorders can be extremely painful. LCH of the skin is often misdiagnosed as another skin disorder until a biopsy (a sample of the tissue) is performed. LCH located only in the skin can occur in children younger than 1 year old. This form of the disease often goes away on its own. LCH of the bones can cause pain and swelling in the skull, jaw, spine, hips, or other areas. In rare cases, LCH can affect the brain, causing problems with balance, speech, and coordination. These effects are similar to those seen in Erdheim-Chester disease. LCH that affects limited parts of the body may be treated with localized treatments. These include the removal of tumors and skin treatments. More-extensive LCH may require chemotherapy, radiation, or drugs that target particular gene mutations.