(Idiopathic Inflammatory Myopathy)
Dermatomyositis is an inflammatory disease which causes swelling and redness 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 harmful bacteria in your body. An autoimmune disorder means the immune system begins to attack normal, healthy tissue.
An infection may trigger dermatomyositis, such as Coxsackie B virus, group A streptococcus, or echovirus.
Your chance of developing dermatomyositis is higher if you have an autoimmune disorder such as:
Dermatomyositis is also associated with certain genes.
Dermatomyositis may cause:
Skin changes such as:
- Violet-colored, bumpy, or scaly skin rash, especially around the eyes (heliotrope rash), upper back, elbows, or knuckles
- Itching, especially the scalp
- Sensitivity to sunlight
- Nail changes
- Skin nodules
problems such as:
- Weakness especially in hips, thighs, arms or neck
- Aching pain in legs, shoulder, arm, or neck
- Tender muscles
- Difficulty swallowing and speaking
- Weight loss
- Aching and color changes in fingers, especially in cold temperatures
- Shortness of breath
You will be asked about your symptoms and medical history. A physical exam will be done. You may be referred to a specialist for further evaluation.
Your bodily fluids and tissues may be tested. This can be done with:
- Blood tests
- Muscle biopsy
Your muscles may be tested. This can be done with an electromyogram (EMG).
Your breathing ability (pulmonary function) may also be tested
Images may be taken of your bodily structures. This can be done with:
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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 exercises
- Guidelines for a general exercise program
- Tips to modify day to day activities if muscle weakness is affecting them
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. They can also increase infections. To lower these effects, you will be given the lowest dose needed to control your symptoms. You may also be asked to take supplements 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.
Intravenous Immune Globulin
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.
The Myositis Association
National Institute of Neurological Disorders and Stroke
The Arthritis Society
Muscular Dystrophy Canada
Chung L, Genovese MC, et al. A pilot trial of rituximab in the treatment of patients with dermatomyositis. Arch Dermatol. 2007;143:763-767.
Dermatomyositis. National Institute of Neurological Disorders and Stroke website. Available at: http://www.ninds.nih.gov/disorders/dermatomyositis/dermatomyositis.htm. Updated July 27, 2015. Accessed May 5, 2016.
Dermatomyositis. EBSCO Dynamed Plus website. Available at:http://www.dynamed.com/topics/dmp~AN~T116942/Dermatomyositis. Updated November 20, 2017. Accessed January 16, 2018.
Dold S, Justiniano ME, et al. Treatment of early and refractory dermatomyositis with infliximab: a report of two cases. Clin Rheumatol. 2007;26:1186-1188.
Wong EH, Hui AC, et al. MRI in biopsy-negative dermatomyositis. Neurology. 2005;64:750.
Last reviewed May 2018 by Michael Woods, MD Last Updated: 1/10/2018