Dermatomyositis is an inflammatory condition that causes muscle inflammation, progressive weakness and skin rashes. Dermatomyositis is part of a larger group of inflammatory muscle conditions (inflammatory myopathies) that includes polymyositis and inclusion body myositis. 

The first signs of dermatomyositis include fatigue, muscle weakness, stiffness or soreness, a reddish-purple skin rash that is often painful and itchy and can be found on the eyelids, cheeks and nose (“butterfly rash”), back, upper chest, elbows, knees, knuckles and other regions. As symptoms progress patients may experience hyperpigmentation or depigmentation of the skin, difficulty swallowing, breathing problems, abnormal calcium deposits and accumulation of fluid in tissues, joint pain and more.

It’s unknown exactly what causes dermatomyositis, though it is thought to result from a problem with an immune response to the body’s own tissues. Genetic, immune and environmental factors may all play a role in a person’s risk for developing dermatomyositis. Like with many autoimmune conditions, the severity of symptoms may vary over the course of a person’s life.

While people of any age can be affected, dermatomyositis most often affects adults ages 40 to 60. The symptoms of juvenile (childhood) dermatomyositis are similar to the symptoms seen in adults, but the onset is usually more sudden. Females are twice as likely to be diagnosed with dermatomyositis, and in the U.S, Black women have been found to be particularly susceptible. 

Treatment for dermatomyositis is mostly focused on symptom management. Skin rashes may be treated with topical steroids, various other drugs and sun avoidance. Patients may also receive physical therapy to address muscle weakness. Additionally, Individuals with dermatomyositis are often treated with steroid hormones called glucocorticoids or immunosuppressants. In 2021, the FDA approved the first targeted treatment for adults with dermatomyositis, an intravenous immune globulin (IVIG) therapy called Octagam® 10%. Skin rashes may be treated with topical steroids, various other drugs and sun avoidance. Patients may also receive physical therapy to address muscle weakness.