Dermatomyositis is an inflammatory disease of the muscle (myositis), skin and blood vessels characterized by inflammation and a skin rash. It is a type of inflammatory myopathy. Myopathy is a muscular disease in which the muscle fibers do not function for any one of many reasons, resulting in muscular weakness. The cause of most inflammatory myopathies is unknown; however, the leading theory is that abnormalities in the body's immune system may lead to inflammation and damage to muscle cells or the blood vessels that are in the muscle and skin.
Anyone can develop the disease, but it most commonly occurs in children age 5 - 15 (Juvenile Dermatomyositis) and adults age 40 - 60. Women develop this condition more often than men do.
Symptoms include difficulty swallowing, muscle weakness, stiffness or soreness, purple or violet colored upper eyelids, purple-red skin rash or shortness of breath. Dermatomyositis may be associated with collagen-vascular or autoimmune diseases, such as lupus.
The disease is treated with anti-inflammatory medicines called corticosteroids and drugs that suppress the immune system. Most cases of dermatomyositis respond to therapy. The disease is usually more severe and resistant to therapy in individuals with cardiac or pulmonary problems.