Dermatomyositis is an inflammation of muscle and skin.
The exact cause of dermatomyositis is not known. It may be an autoimmune disorder. The immune system identifies and attacks viruses and bad bacteria in your body. An autoimmune disorder means the immune system begins to attack normal healthy tissue.
A viral infection may trigger the onset of dermatomyositis.
Dermatomyositis may cause:
Skin changes such as:
Violet-colored, bumpy, or scaly skin rash (especially around the eyes, upper back, elbows, or knuckles)Itching, especially the scalpSensitivity to sunlightCalcium deposits
problems such as:
Weakness especially in hips, thighs, arms or neckAching pain in legs, shoulder, arm, or neckTender musclesDifficulty swallowing and speakingAching and color changes (red, white, and blue) in fingers, especially in cold temperaturesJoint painShortness of breath
Your doctor will ask about your symptoms and medical history. A physical exam will be done. You may be referred to a specialist for further evaluation.
Blood tests may be done to look for infections or signs of muscle damage and inflammation.
Your doctor may also do a series of tests on the muscle including: Electromyogram (EMG)
—to test muscle activity
—to take a sample of muscle tissue
Magnetic resonance imaging (MRI)
or ultrasound—to detect inflammation in your muscles.
Other tests that may be done to help rule out other conditions or complications include: Skin biopsy—to take a sample of skin tissueCancer tests—dermatomyositis is associated with cancer about 15% of the timeCAT scan (CT)
—to look for any lung involvement
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There is no cure for dermatomyositis. Treatment is focused on managing the symptoms. Talk with your doctor about the best treatment plan for you. Treatment options include the following:
You may be referred to a physical therapist. The therapist will help improve or prevent the loss of muscle strength and function. It may include: Strength and flexibility exercisesGuidelines for a general exercise programTips to modify day to day activities if muscle weakness is interfering
Corticosteroids can suppress your immune system. This will decrease inflammation in the muscle. Steroid medication can also be used on the skin to relieve skin symptoms. Corticosteroids can cause problems, like lower bone density. To lower this effect your doctor will use the lowest dose needed to control your symptoms. You may also be asked to take supplement like calcium and vitamin D to improve your bone strength.
There are other medication options that can help to suppress the immune system. They may be used with or instead of the corticosteroids.
Immune globulin has healthy antibodies from several donors. These antibodies can block the unhealthy antibodies associated with dermatomyositis. It is given through an IV.
The infusion needs to be repeated every few weeks.
Regular exercise can help you develop and maintain muscle strength. Modify the program as needed to prevent irritating your condition. Check with your doctor and physical therapist for exercise guidelines. Rest when needed.
Your skin may also be more sensitive to the sun. Use sunscreen or cover your skin with clothes or a hat.
There are no known ways to prevent dermatomyositis.
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Last reviewed November 2012 by Michael Woods, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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