Dermatomyositis (dur-muh-toe-mi-uh-SI-tis) is an uncommon inflammatory disease marked by muscle weakness and a distinctive skin rash. Medically, polymyositis is classified as a chronic inflammatory myopathy — one of only three such diseases.
Dermatomyositis affects adults and children alike. In adults, dermatomyositis usually occurs from the late 40s to early 60s; in children, the disease most often appears between 5 and 15 years of age. Dermatomyositis affects more females than males.
Periods of remission, when symptoms of dermatomyositis improve spontaneously, may occur. Treatment can clear the skin rash and help you regain muscle strength and function.
The most common signs and symptoms of dermatomyositis include:
Other dermatomyositis signs and symptoms that may occur include:
When to see a doctor
The exact cause of dermatomyositis is unknown, but the disease shares many characteristics with autoimmune disorders, in which your immune system attacks normal body components.
Normally, your immune system works to protect your healthy cells from attacks by foreign substances, such as bacteria and viruses. If you have polymyositis, an unknown cause may act as a trigger for your immune system to begin producing autoimmune antibodies (autoantibodies) that attack your body's own tissues. Many people with polymyositis show a detectable level of autoantibodies in their blood.
Small blood vessels in muscular tissue are particularly affected in dermatomyositis. Inflammatory cells surround the blood vessels and eventually lead to degeneration of muscle fibers.
Possible complications of dermatomyositis include:
Muscle weakness complications
Skin symptom complications
Concerns during pregnancy
Preparing for your appointment
You'll probably first bring your symptoms to the attention of your family doctor, who may refer you to a rheumatologist — a doctor who specializes in the treatment of arthritis and other diseases of the joints, muscles and bone.
What you can do
Prepare a list of questions ahead of time to help make the most of your limited time with your doctor. For dermatomyositis, some basic questions to ask your doctor include:
In addition to the questions that you've prepared in advance, don't hesitate to ask your doctor questions during your appointment if you think of something new.
What to expect from your doctor
Tests and diagnosis
Dermatomyositis is the most easily recognized of the inflammatory muscle diseases because of its characteristic rash. Occasionally, a rash alone may prompt a diagnosis of dermatomyositis (called amyopathic dermatomyositis), even if you don't have any muscle weakness.
In addition to assessing your signs and symptoms, your doctor may use other tests to confirm a diagnosis of dermatomyositis:
Treatments and drugs
There's no cure for dermatomyositis, but treatment can improve your skin and your muscle strength and function. The earlier treatment is started in the course of dermatomyositis, the more effective it is, leading to fewer complications.
However, as with many conditions, no single approach is best; your doctor will tailor your treatment strategy based on your symptoms and how well they respond to therapy.
Corticosteroids are medications that suppress your immune system, limiting the production of antibodies and reducing muscle inflammation, as well as improving muscle strength and function. Your doctor may also prescribe topical corticosteroids for your skin.
Your doctor may prescribe a high dose to begin with, and then decrease it as your signs and symptoms improve. Improvement generally takes about two to four weeks, but you may take the medication for several months. Prolonged use of corticosteroids can have serious and wide-ranging side effects, which is why your doctor may gradually taper the dose of medication down to low levels.
Because of the potential for serious side effects, your doctor may recommend supplements to combat them, such as calcium and vitamin D.
Additional immunosuppressive therapies
However, there aren't many scientific studies to date about the effectiveness of these agents on dermatomyositis. If your doctor prescribes one of these medications, he or she will closely monitor you to make sure the medication is working and to check for side effects. These medications can be expensive and, because they're experimental for treating dermatomyositis, may not be covered by insurance.
Other treatment approaches
Lifestyle and home remedies
With dermatomyositis, areas affected by your rash are more sensitive to the sun. As a precaution, wear protective clothing or high-protection sunscreen when you go out.
Coping and support
Living with a chronic autoimmune disease can make you wonder at times whether you're up to the challenge. To help you cope, try supplementing your medical care with the following suggestions:
Last Updated: 2011-07-07
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