Polymyositis

<B>Polymyositis:</B> A chronic inflammatory disease of muscle that begins when white blood cells, the immune cells of inflammation, spontaneously invade muscles, especially the muscles closest to the trunk or torso, resulting in sometimes severe muscle pain, tenderness and weakness.

There are commonly periods of increased symptoms, called flares or relapses, and periods of decreased symptoms, known as remissions.

The disease is slightly more common in females than males.

It affects all age groups, although its onset is most common in middle childhood and in the twenties.

It occurs throughout the world.

It can be associated with skin rash and is then referred to as 'dermatomyositis.' It also can affect other areas of the body and is, therefore, a systemic illness.

Occasionally, polymyositis is associated with other diseases of connective tissue such as systemic lupus erythematosus, scleroderma, and rheumatoid arthritis.

Polymyositis is also associated with modestly increased risk of cancer, including non-Hodgkin lymphoma, lung and bladder cancer.

There are many other aspects to this important disease that are beyond the scope of this dictionary entry.

For fuller information, please read the article on Polymyositis.