Definition Histiocytosis refers to a group of disorders in which there is an abnormal amount of scavenger cells, called histiocytes, in the blood.
What is going on in the body? There are histiocytosis diseases that affect adults and those that affect children. In adults, the lungs are affected. There is inflammation of the small airways and small blood vessels in the lungs. It is often linked with cigarette smoking. In children the bones are affected. In many cases the skull is involved. However, any other single site or multiple sites can be affected.
What are the signs and symptoms of the condition? Signs and symptoms of histiocytosis differ for adults and children.
What are the causes and risks of the condition? Although the cause of histiocytosis is unknown, it is much more likely to occur in a person who smokes cigarettes.
What can be done to prevent the condition? There is no known prevention for histiocytosis. A person who stops smoking can reduce his or her risk of lung involvement.
How is the condition diagnosed? In adults, the diagnosis of histiocytosis is made by:
bronchoscopy, in which a small sample of the airways are removed and the airways are examined through a small scope
pulmonary function tests, a group of tests that measure the lungs' capacity to hold air, move air in and out, and exchange oxygen and carbon dioxide
In children the diagnosis is made by:
bone x-rays that show the "punched-out" appearance of bone lesions
x-rays of the entire body, to determine how much bone is involved
biopsies, or small samples, taken from the bone, bone marrow, and skin
blood tests
What are the long-term effects of the condition? The long-term effects of histiocytosis in children can be quite significant, even resulting in death. Usually this disease stabilises in about half of the affected people. The others end up with permanent loss of lung function.
What are the risks to others? There are no risks to others, as histiocytosis is not contagious.
What are the treatments for the condition? Histiocytosis is treated with corticosteroids, such as prednisone and methotrexate. These help reduce inflammation in the lungs. Other medications, such as cyclophosphamide, may also be tried. However, no therapy clearly helps this disease. Sometimes radiation therapy is used to treat bone lesions. A person who smokes should stop smoking.
What are the side effects of the treatments? Side effects vary depending on the medication, but may include allergic reactions.
What happens after treatment for the condition? Complications can occur with histiocytosis. A sudden collapse of the lung, known as atelectasis, is common. This disorder can lead to death due to lung or heart failure.
How is the condition monitored? A series of x-rays and pulmonary function tests may be needed to see how the histiocytosis changes over time. Any new or worsening symptoms should be reported to the doctor.
Author: James Broomfield, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
