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Medical Author:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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Medical Editor:

Dennis Lee, MD

Dennis Lee, MD

Dr. Lee was born in Shanghai, China, and received his college and medical training in the United States. He is fluent in English and three Chinese dialects. He graduated with chemistry departmental honors from Harvey Mudd College. He was appointed president of AOA society at UCLA School of Medicine. He underwent internal medicine residency and gastroenterology fellowship training at Cedars Sinai Medical Center.

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In this Article

• What is polymyositis?
• What causes polymyositis?
• What are symptoms of polymyositis?
• How does the doctor diagnose polymyositis?
• How is polymyositis treated?
• Polymyositis At A Glance
• Patient Comments: Polymyositis - Symptoms and Signs
• Patient Comments: Polymyositis - Effective Treatments
• Find a local Rheumatologist in your town
• Polymyositis Index

Weakness of muscles is the most common symptom of polymyositis. The muscles involved usually are those that are closest to the trunk of the body. The onset can be gradual or rapid. This results in varying degrees of loss of muscle power and atrophy. The loss of strength can be noticed as difficulty getting up from chairs, climbing stairs or lifting above the shoulders. Trouble with swallowing and weakness lifting the head from the pillow can occur. Occasionally, the muscles ache and are tender to the touch (25% of patients).

Patients can also feel fatigue, a general feeling of discomfort and have weight loss and/or low-grade fever.

With skin involvement (dermatomyositis), the eyes can be surrounded by a violet discoloration with swelling. There can be scaly reddish discoloration over the knuckles, elbows, and knees (Gottron's sign). There can also be reddish rash on the face, neck, and upper chest. Hard lumps of calcium deposits can develop in the fatty layer of the skin, most commonly in childhood dermatomyositis.

Heart and lung involvement can lead to irregular heart rhythm, heart failure, and shortness of breath.

Because polymyositis can present in combination with other illnesses (see related articles on systemic lupus erythematosus, scleroderma and rheumatoid arthritis), it can also have overlap features with them. These illnesses are discussed elsewhere.

Both polymyositis and dermatomyositis can sometimes be associated with cancers, including lymphoma, breast cancer, lung cancer, ovarian cancer, and colon cancer. The cancer risk is reported to be much greater with dermatomyositis than polymyositis.