Myositis
What is it?
Myositis is defined as the inflammation of muscles (“myo” means muscle and “itis” means inflammation). The inflammatory myopathies are a group of disorders characterized by inflammation and weakness mainly of the muscles closest to the trunk of the body (proximal muscles). These disorders include polymyositis, dermatomyositis and inclusion body myositis. Myositis may be associated with inflammation in other organs, including the joints, heart, lungs, intestines and skin. In dermatomyositis, a rash develops in addition to the muscle inflammation.
Muscle inflammation also can occur in people with other rheumatic diseases, such as rheumatoid arthritis, lupus and scleroderma.
Many people with myositis respond well to treatment. Some people have a single attack and are able to stop taking medications after about a year. Others have recurrent attacks of the disease that do respond to medication. Although less common, some people experience chronically active myositis and must receive continuous treatment.
