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Polymyositis and Dermatomyositis

What are Polymyositis and Dermatomyositis?

Polymyositis and dermatomyositis are autoimmune conditions in which your immune system starts attacking your body’s own organs and tissues rather than protecting them.

Polymyositis and dermatomyositis are part of a range of conditions known as myositis-spectrum disorders.

What Causes Polymyositis and Dermatomyositis?

The exact cause of polymyositis and dermatomyositis is not known. The potential triggers may include exposure to sunlight, infections and taking certain medications. Other causes include an underlying cancer.

What are the Symptoms of Polymyositis and Dermatomyositis?

The symptoms of polymyositis and dermatomyositis vary from person to person. The most common symptoms are muscle weakness which mainly involves the proximal limb muscles. The symptoms can come on rapidly or may take months or years to appear. The pattern of weakness varies from person to person and may include:

  • Struggling to climb stairs or difficulty getting out of chairs
  • Weakness in the arms and difficulty lifting or raising the arms over the head, such as with washing hair or reaching overhead cupboards
  • Muscle pain, mostly when the onset of symptoms is quick
  • Aching and mild tendernessof the affected muscles

Other symptoms can includeswallowing difficulties, breathing problems and chest pain. In cases of dermatomyositis, the skin may be affected by a rash on the face and exposed parts of the chest and hands.

Contact your doctor immediately if you experience chest pains, shortness of breath, palpitations, or changes in your breathing pattern.

How are Polymyositis and Dermatomyositis Diagnosed?

A diagnosis of polymyositis and dermatomyositis is based on a combination of signs and symptoms, a physical examination, imaging tests such as an MRI, electromyogram, and a muscle biopsy.

How are Polymyositis and Dermatomyositis Treated?

The treatment of polymyositis and dermatomyositis mainly involves medications. Medications commonly prescribed include:

  • Corticosteroids: They help decrease inflammation and improve healing. However, they are associated with side-effects.
  • Immunosuppressants: These work to suppress the action of the immune system and may be beneficial in controlling muscle inflammation, and eventually to reduce and stop the use of steroids.
  • High-dose intravenous immunoglobulin is prescribed in severe cases.