Dermatomyositis (DM) is the most recognized of the Inflammatory Myopathies due to it's distinctive rash.  This rash occurs as a patchy, dusky, reddish or lilac rash on the eyelids, cheeks, and bridge of nose, and on the back or upper chest, elbows, knees, and knuckles.  Some people with DM develop calcified nodules or hardened bumps under the skin.

Muscle weakness usually develops over a period of weeks but may develop over months or even days.  The weakness initially affects those muscles closest to and within the trunk of the body, including neck, hip, trunk, and shoulder.  Difficulty swallowing occurs in at least one third of DM patients.  Whereas less than 25% of adults report muscle pain, more than 50% of children with DM complain of muscle pain and tenderness.

Dermatomyositis can occur at any age from childhood to adulthood and is more common in females than males.

High dose Prednisone (an immunosuppressant) has been an effective treatment for many patients.  Other immunosuppressants such as Azathioprine and Methotrexate are used.  Unfortunately, these drugs have adverse side effects, especially after prolonged use.  For some patients who do not respond well to Prednisone, intravenous administration of immunoglobulin (IVIg) has helped some patients, but it is very expensive - $7,000 to $28,000 plus per infusion.