Dermatomyositis is a rare muscle disease. It causes inflammation and weakness in the muscles and also causes a skin rash. It can also cause joint pain, and inflammation of the heart, lung, and blood vessels. It often starts with a rash that's itchy, burning, patchy, and reddish or purple. The rash shows up on the eyelids, cheeks, nose, back, upper chest, elbows, knees, and knuckles. As the disease gets worse, there is muscle weakness and tenderness. The swallowing muscles may also be affected. You may also develop hard bumps under the skin.

Experts don't know what causes dermatomyositis. But it may be an autoimmune disorder. It may occur in anyone, at any time from infancy through old age. But it most often occurs in women between ages 40 and 60. In children, the symptoms often appear between ages 5 and 15.

This condition is treated with oral steroids. These slow down the disease's progression. Other medicines may also be used. Sometimes, immune suppressing medicines such as azathioprine or methotrexate may be started at the same time as oral steroids. This helps prevent some of the complications of long-term steroid use. In some cases, these medicines may only be used if oral steroids don't work. Some people will recover completely. Others will need treatment over their lifetime.

Dermatomyositis may be linked to a higher risk of certain types of cancer. These include breast, ovarian, stomach, lung, and colorectal cancer, and non-Hodgkin lymphoma. Your healthcare provider may do periodic screening exams.

Home care

These guidelines will help you care for yourself at home:

  • The rash is sensitive to sunlight. Protect yourself from the sun with hats and cover-up clothing and use sunscreen of at least SPF 30.

  • If you have muscle aches, rest as needed.

  • Light exercise and physical activity can help keep your muscles in the best shape possible. Talk with your healthcare provider about an exercise plan that's right for you. You may need to see a physical therapist.

  • You may use over-the-counter medicine as directed to control pain, unless another medicine was prescribed. Talk with your provider before using these medicines if you have chronic liver or kidney disease. Also talk with your provider if you ever had a stomach ulcer or gastrointestinal bleeding. If you were prescribed prednisone, don’t take ibuprofen or other nonsteroidal anti-inflammatory drugs (NSAIDs).

  • Talk with your provider before trying to get pregnant.

Follow-up care

Follow up with your healthcare provider, or as advised. For more information, contact:

When to get medical care

Call your healthcare provider right away if any of these occur.

  • A small amount of blood in the stool (black or red color)

  • Change in bowel or bladder habits

  • Cough or hoarseness that doesn't go away

  • Trouble swallowing

  • Fever of 100.4ºF (38ºC) or higher, or as advised by your provider

  • Belly pain

  • Thickening or lump in the breast or elsewhere

  • Unexpected weight loss

  • Vision changes

Call 911

Call 911 if you have:

  • Dizziness, fainting

  • Shortness of breath

  • Weakness 

  • A large amount of blood in the stool (black or red color)

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