Myositis means inflammation of the muscles that you use to move your body. An injury, infection, or autoimmune disease can cause it. Two specific kinds are polymyositis and dermatomyositis. Polymyositis causes muscle weakness, usually in the muscles closest to the trunk of your body. Dermatomyositis causes muscle weakness, plus a skin rash.
Other symptoms of myositis may include:
- Fatigue after walking or standing
- Tripping or falling
- Trouble swallowing or breathing
Doctors may use a physical exam, lab tests, imaging tests and a muscle biopsy to diagnose myositis. There is no cure for these diseases, but you can treat the symptoms. Polymyositis and dermatomyositis are first treated with high doses of a corticosteroid. Other options include medications, physical therapy, exercise, heat therapy, assistive devices, and rest.
NIH: National Institute of Neurological Disorders and Stroke
- Dermatomyositis: Signs and Symptoms (Muscular Dystrophy Association)
Diagnosis and Tests
- ANA (Antinuclear Antibody) Test (National Library of Medicine) Also in Spanish
- Dermatomyositis: Diagnosis (Muscular Dystrophy Association)
- Electromyography (EMG) and Nerve Conduction Studies (National Library of Medicine) Also in Spanish
- Inclusion-Body Myositis: Diagnosis (Muscular Dystrophy Association)
- Polymyositis: Diagnosis (Muscular Dystrophy Association)
- Dermatomyositis (DM) (American Osteopathic College of Dermatology)
- Inclusion Body Myositis (National Institute of Neurological Disorders and Stroke)
- Inflammatory Myopathies (National Institute of Neurological Disorders and Stroke)
- Polymyositis (Mayo Foundation for Medical Education and Research) Also in Spanish
- Idiopathic inflammatory myopathy: MedlinePlus Genetics (National Library of Medicine)
Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine)
- Article: Association of anti-Ro52 autoantibody with interstitial lung disease in autoimmune diseases:...
- Article: Clinical characteristics and prognostic analysis of idiopathic inflammatory myopathy with positive...
- Article: Comparison of machine learning methods in the early identification of vasculitides,...
- Myositis -- see more articles
Find an Expert
- Find a Rheumatologist (American College of Rheumatology)
- National Institute of Arthritis and Musculoskeletal and Skin Diseases Also in Spanish
- National Institute of Neurological Disorders and Stroke Also in Spanish