Learn About Dermatomyositis
Dermatomyositis is a disease that involves muscle inflammation and a skin rash. Polymyositis is a similar inflammatory condition that also involves muscle weakness, swelling, tenderness, and tissue damage but no skin rash. Both are part of a larger group of diseases called myopathies, more specifically inflammatory myopathies.
The cause of dermatomyositis is unknown. Experts think it may be due to a viral infection of the muscles or a problem with the body's immune system. It may also occur in people who have cancer in the abdomen, lung, or other parts of the body.
Anyone can develop this condition. It most often occurs in children age 5 to 15 and adults age 40 to 60. It affects women more often than men.
Symptoms may include:
- Muscle weakness, stiffness, or soreness
- Purple color to the upper eyelids
- Purple-red skin rash
- Shortness of breath
- Difficulty swallowing
The muscle weakness may come on suddenly or develop slowly over weeks or months. You may have trouble raising your arms over your head, getting up from a sitting position, and climbing stairs.
The rash may appear on your face, knuckles, neck, shoulders, upper chest, and back.
The initial treatment is the use of corticosteroid medicines. The dose of medicine is slowly tapered off as muscle strength improves. This takes about 4 to 6 weeks. You may stay on a low dose of a corticosteroid medicine after that.
Medicines to suppress the immune system may be used to replace the corticosteroids. These medicines may include azathioprine, methotrexate or mycophenolate.
Treatments that may be tried when disease that remains active in spite of these medicines are:
- Intravenous gamma globulin
- Biologic medicines
When your muscles get stronger, your provider may tell you to slowly cut back on your doses. Many people with this condition must take a medicine called prednisone for the rest of their lives.
If a tumor is causing the condition, the muscle weakness and rash may get better when the tumor is removed.
Johns Hopkins Bayview Medical Center
Andrew Mammen is a Neuromusculoskeletal Medicine specialist and a Neurologist in Baltimore, Maryland. Dr. Mammen is rated as an Elite provider by MediFind in the treatment of Dermatomyositis. His top areas of expertise are Myositis, Polymyositis, Dermatomyositis, and Necrotizing Myopathy (NM).
Johns Hopkins Bayview Medical Center
Dr. Christopher-Stine is the Co-Founder and Director of the Johns Hopkins Myositis Center. She is a Professor of Medicine and Neurology. She is a longstanding core faculty member of the Johns Hopkins University School of Medicine College Advisory Program and serves as the Co-Chair of the Johns Hopkins Institutional Review Board (IRB 5). Dr. Christopher-Stine graduated Cum Laude with a B.A. in chemistry from Franklin and Marshall College; was elected to Alpha Omega Alpha at Hahnemann University School of Medicine, where she received her MD degree, and she attained her Masters of Public Health degree from the Johns Hopkins Bloomberg School of Public Health. Her internship and residency training were completed at MCP Hahnemann University, where she also served as Chief Resident. She pursued her rheumatology fellowship training at Johns Hopkins. Dr. Christopher is rated as an Elite provider by MediFind in the treatment of Dermatomyositis. Her top areas of expertise are Myositis, Polymyositis, Dermatomyositis, and Inclusion Body Myositis.
Johns Hopkins Bayview Medical Center
Dr. Christopher A. Mecoli is an Associate Professor of Medicine at the Johns Hopkins University School of Medicine. His area of clinical expertise is rheumatology. A physician-scientist, Dr. Mecoli serves on the faculty of Johns Hopkins Myositis Center and Johns Hopkins Scleroderma Center. He earned his M.D. from Rutgers New Jersey Medical School. He completed an internal medicine residency at the Hospital of the University of Pennsylvania and a rheumatology fellowship at Johns Hopkins. He also holds an M.H.S. in clinical investigation from the Johns Hopkins Bloomberg School of Public Health. Dr. Mecoli is rated as an Elite provider by MediFind in the treatment of Dermatomyositis. His top areas of expertise are Dermatomyositis, Myositis, Scleroderma, and Polymyositis.
It is important to be followed by a health care provider when you have dermatomyositis. Severe illness can lead to disability and can sometimes result in death.
Symptoms may go away completely in some people, such as children.
The condition may be fatal in adults due to:
- Severe muscle weakness
- Malnutrition
- Pneumonia
- Lung failure
The major causes of death with this condition are cancer and lung disease.
People with lung disease with the anti-MDA-5 antibody have a poor prognosis in spite of current treatment.
Complications may include:
- Lung disease
- Acute renal failure
- Cancer (malignancy)
- Inflammation of the heart
- Joint pain
Contact your provider if you have muscle weakness or other symptoms of this condition.
Background: * Like other complex diseases, autoimmune diseases are the result of numerous causes, including genetic and environmental factors. Some researchers believe that people who are susceptible to autoimmune disorders develop them when the body reacts to environmental or other factors by creating white blood cells that attack the body s own tissues, which then progresses to autoimmune diseases. These im...
Summary: This study will evaluate subjects with adult- and childhood-onset myositis to learn more about their cause and the immune system changes and medical problems associated with them. Myositis is an inflammatory muscle disease that can damage muscles and other organs, resulting in significant disability. Children or adults with polymyositis or dermatomyositis or a related condition may be evaluated un...
Published Date: January 28, 2025
Published By: Diane M. Horowitz, MD, Rheumatology and Internal Medicine, Northwell Health, Great Neck, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
Dinulos JGH. Connective tissue diseases. In: Dinulos JGH, ed. Habif's Clinical Dermatology. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 17.
Greenberg SA. Inflammatory myopathies. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 248.
Nagaraju K, Aggarwal R, Lundberg IE. Inflammatory diseases of muscle and other myopathies. In: Firestein GS, McInnes IB, Koretzky GA, Mikuls TR, Neogi T, O'Dell JR, eds. Firestein & Kelley's Textbook of Rheumatology. 12th ed. Philadelphia, PA: Elsevier; 2025:chap 86.
National Organization for Rare Disorders website. Dermatomyositis. rarediseases.org/rare-diseases/dermatomyositis/. Updated May 4, 2018. Accessed February 27, 2025.