Dermatomyositis is an inflammatory disease that causes muscle weakness and skin rashes.

Dermatomyositis is a rare disease that is more common in women than in men. Adults most often develop dermatomyositis between the ages of 45 and 60. There is also a childhood form of the disease called juvenile dermatomyositis.

A violet rash develops, most commonly on your face and eyelids. The rash can also appear on your knuckles, chest, knees, nails, and back. The purple, patchy rash is often the first sign of dermatomyositis.

Dermatomyositis also causes muscle weakness that tends to start in the trunk area, such as your hips, shoulders, neck, upper arms, and thighs. The weakness tends to get gradually worse.

There is no cure for dermatomyositis. However, the sooner treatment is started, the better the results. It is important to keep in touch with your doctors during treatment.