Causes

The cause is unknown, but it may result from either a viral infection or an autoimmune reaction. In the latter case it is a systemic autoimmune disease. Many people diagnosed with dermatomyositis were previously diagnosed with infectious mononucleosis and Epstein-Barr virus. Some cases of dermatomyositis actually "overlap" (are combined with) other autoimmune diseases

Several cases of polymyositis and dermatomyositis were reported as being triggered by the use of various statin drugs used to control blood cholesterol. Muscle biopsies of these patients showed rhabdomyolysis, and degeneration and regeneration of muscle tissue.

Presentation

X-ray findings sometimes include dystrophic calcifications in the muscles, and patients may or may not notice small calcium deposits under the skin. Many do not have any calcium deposits of any kind. The rash also may come and go, and may not be dependent on the severity of the muscle involvement at the time. "Gottron's papules", pink patches on the knuckles and other extensor surfaces, and priapism, are associated with this disorder. Another concern is interstitial lung disease.

Classification

Dermatomyositis is a type of autoimmuneconnective tissue disease. It is related to polymyositis and inclusion body myositis.

Diagnosis

The diagnosis of dermatomyositis can be confirmed by muscle biopsy, EMG,and blood tests. It should be noted, however, that only muscle biopsy is truly diagnostic (pathognomonic); liver enzymes and EMG are relatively non-specific

Signs and symptoms

The main symptoms include skin rash and symmetricproximalmuscle weakness which may be accompanied by pain. The pain may resemble the type experienced after strenuous exercise. Some dermatomyositis patients have little pain, while in others (esp. in JDM), the pain may be severe. It is important to remember that this condition varies from person to person in many ways. Also in many cases muscle may deteriorate and render the patient temporarily paralyzed unable to walk, run, get out of bed, or even swallow food and liquids.

Treatment

This disease has no known cure. Specialized exercise therapy may supplement treatment to enhance quality of life.

Medications to help relieve symptoms include:

• Prednisolone

• Methotrexate

• Mycophenolate (CellCept / Myfortic)

• Intravenous immunoglobulin

• Azathioprine

• Cyclophosphamide

• Rituximab

Dermatomyositis: From Wikipedia,