Department of Pediatrics

Dermatomyositis is a noninfectious inflammation of muscle tissue and skin.

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

They are all believed to represent “autoimmune disorders,” where the body launches an attack against its own tissue. These chronic, progressive conditions lead to tissue destruction. They are potentially serious conditions that require care from your doctor. The sooner these disorders are treated, the more favorable the outcome. If you suspect you have dermatomyositis, contact your doctor immediately.

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 misidentify infected skin and muscle tissue as a threat.

The following factor increases your chance of developing dermatomyositis:

• Having another connective tissue disorder

If you experience 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 experience any one of the following symptoms, see your physician.

• 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) —to test the electrical responsiveness of your muscles. This test involves inserting tiny needles into affected muscles and stimulating them with tiny electrical currents.
• Muscle biopsy —surgical removal of a small piece of muscle to examine it under a microscope
• Magnetic resonance imaging (MRI) or ultrasound—to help detect inflammation in your muscles
• Skin biopsy—surgical removal of a small piece of skin to examine it under a microscope
• Cancer tests—in adults, associated with cancer about 15% of the time, may be the first sign of cancer
• CAT scan (CT) —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  

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

There are no known ways to prevent dermatomyositis.