Dermatomyositis is a muscle disease that causes inflammation and a skin rash. It is a type of inflammatory myopathy.
Causes, incidence, and risk factors:
The cause is unknown. Experts think it may be due to a viral infection of the muscles or a problem with the body's immune system.
Anyone can develop dermatomyositis, but it most commonly occurs in children age 5 to 15 and adults age 40 - 60. Women develop this condition more often than men.
Polymyositis is a similar condition, but the symptoms occur without a skin rash.
The muscle weakness may appear suddenly or occur slowly over weeks or months. You may have difficulty raising your arms over the head, rising from a sitting position, and climbing stairs.
The rash may appear over the face, knuckles, neck, shoulders, upper chest, and back.
Signs and tests:
The doctor will perform a physical exam. Tests may include:
Bloods test to check levels of creatine phosphokinase and aldolase
The disease is treated with anti-inflammatory medicines called corticosteroids and drugs that suppress the immune system.
When your muscle strength gets better, your doctor may tell you to slowly cut back on your doses. However, most persons with this condition must take a medicine called prednisone indefinitely.
If the condition is associated with a tumor , the muscle weakness and rash may improve when the tumor is removed.
Support Groups:
Expectations (prognosis):
Some people may recover and have symptoms completely disappear. Doctors have reported several such cases, especially in children.
In adults, death may result from severe and prolonged muscle weakness, malnutrition, pneumonia , or lung failure. The major causes of death are cancer (malignancy) and lung disease.
Review Date: 12/24/2007 Reviewed By: David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.; and Paul H. Plotz, MD, Chief, Arthritis and Rheumatism Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases. Previously reviewed by Kevin Berman, MD, PhD, Associate, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network (4/12/2007).
