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What are polymyositis and dermatomyositis?

Myositis means inflammation of the muscles (myo = muscle, itis = inflammation). 

Polymyositis affects many areas (poly = many), mainly the larger muscles like those around your shoulders, hips and thighs. When polymyositis develops alongside a skin rash, the condition is called dermatomyositis (derm = skin).

Both conditions are autoimmune diseases, which means your immune system attacks your body’s own tissues.


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