Polymyositis & Dermatomyositis

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  • Polymyositis is a disease that causes muscles to be weak. After a person has had polymyositis for a long time his or her muscles can get smaller.
  • Polymyositis can affect the muscles in any part of the body. It can also affect the lungs and the heart.
  • It is called dermatomyositis when the skin is also affected. It can cause skin rashes all over the body.
  • Both polymyositis and dermatomyositis are chronic diseases.
  • With both forms of the disease, there may be times when the symptoms are stronger (active periods) and then periods when the symptoms lessen (remissions).
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How common are polymyositis and dermatomyositis?
What are the warning signs of polymyositis and dermatomyositis?
What causes polymyositis and dermatomyositis?
How are polymyositis and dermatomyositis diagnosed?

There is no cure for polymyositis and dermatomyositis. The goal of treatment is to help in the management of symptoms. Establishing the correct diagnosis early is important because something can be done to manage most forms of arthritis. 


Rest is generally recommended during periods of active disease. Exercise should be done when symptoms are under control to keep muscles from becoming too weak. Always consult your doctor before beginning an exercise program. He or she may also be able to refer you to a physical therapist who can advise you of the forms of exercise that are likely to be helpful, and those that could be harmful. If the disease has impaired your breathing, your therapist can instruct you in breathing exercises.

Arthritis medications are designed to control a disease, slow its progression, and to help manage pain. There is a wide range of options – with new ones coming on the horizon – so understanding all possible treatments is not easy. 

These medications can be very complex, so you are encouraged to ask for in-depth explanations from your health care team – including pharmacists, who are an excellent source of information. 

To explore this area of treatment, The Arthritis Society has developed a comprehensive expert guide that delivers detailed information on medications used to treat arthritis.

Explore the Arthritis Medications A Reference Guide

The optimal treatment is what is best in each individual case – so speak with your doctor and/or pharmacist about what kind of medications are most appropriate for you.

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