Dermatomyositis is a noninfectious inflammation of muscle tissue and skin.

Dermatomyositis and its sister disease, polymyositis, belong to a large group of connective tissue disorders that includes lupus erythematosus, rheumatoid arthritis, and scleroderma (systemic sclerosis).

They are all believed to be “autoimmune disorders,” where the body launches an attack against its own tissue. These chronic, progressive conditions lead to tissue damage. They can be serious conditions that require care from your doctor. The sooner these disorders are treated, the better the outcome. If you suspect you have this condition, contact your doctor right away.

Skin Sections

Retina of the Eye
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Although the cause or causes are not known, a viral infection may trigger the onset of dermatomyositis by causing the body’s immune system to identify infected skin and muscle tissue as a threat.

Risk Factors

Your chance of developing this condition is higher if you have another connective tissue disorder.


If you have any of these symptoms, do not assume it is due to dermatomyositis. These symptoms may be caused by other, less serious health conditions. If you have any one of the following symptoms, see your doctor.

  • Weakness
    • Especially of the hips and thighs (making it difficult to climb stairs or stand)
    • May also occur in arms or neck
  • Aching pain in legs, shoulder, arm, or neck
  • Tender muscles
  • Difficulty swallowing
  • Violet-colored, bumpy, or scaly skin rash (especially around the eyes, upper back, elbows, or knuckles)
  • Itching, especially the scalp
  • Photosensitivity (skin burning or itching upon exposure to sunlight)
  • Aching and color changes (red, white, and blue) in fingers, especially in cold temperatures
  • Joint pain
  • Shortness of breath


Your doctor will ask about your symptoms and medical history and perform a physical exam. You are likely to be referred to a rheumatologist (a doctor who specializes in musculoskeletal disorders).

Tests may include the following:

  • Blood tests
  • Electromyogram (EMG)—This is to test the electrical responsiveness of your muscles. This test involves putting tiny needles into affected muscles and stimulating them with tiny electrical currents.
  • Muscle biopsy—This is a surgical removal of a small piece of muscle to examine it under a microscope.
  • Magnetic resonance imaging (MRI) or ultrasound—This helps to detect inflammation in your muscles.
  • Skin biopsy—This is the surgical removal of a small piece of skin to examine it under a microscope.
  • Cancer tests—In adults, this condition is associated with cancer about 15% of the time. It may be the first sign of cancer.
  • CAT scan (CT)—This is a type of x-ray that uses a computer to make pictures of structures inside of the body, in this case the chest (Dermatomyositis may be associated with lung disease.).

Skin Biopsy

Skin proceedure
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Talk with your doctor about the best treatment plan for you. Treatment options include the following:

General Health Maintenance

Because this is a serious disease with long-term implications, physical exercise, a healthy lifestyle, and a nutritious diet are an integral part of treatment.


Cortisone-like drugs, usually oral prednisone, often produce a satisfactory response over the course of 2-3 months. After this, the dose may be reduced according to the activity of the disease.

Immunosuppressive Drugs

Agents used to treat cancer and organ transplants have helped patients who did not respond to prednisone. Examples of these medicines include:

Experimental Treatments

The following treatments have been used for severe cases:


There are no known ways to prevent dermatomyositis.