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 (National Institute of Neurological Disorders and Stroke)
- Inflammatory Myopathies (National Institute of Neurological Disorders and Stroke) Also in Spanish
- Inflammatory Myopathies (Myositis) (Muscular Dystrophy Association) - PDF Also in Spanish
- Metabolic Myopathies (American College of Rheumatology) Also in Spanish
- Polymyositis (National Institute of Neurological Disorders and Stroke)
- Dermatomyositis: Signs and Symptoms (Muscular Dystrophy Association)
- Polymyositis: Can a Gluten-Free Diet Reduce Symptoms? (Mayo Foundation for Medical Education and Research) Also in Spanish
- Genetics Home Reference: fibrodysplasia ossificans progressiva (National Library of Medicine)
- Genetics Home Reference: idiopathic inflammatory myopathy (National Library of Medicine)
Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine)
- Article: Evidence supports blind screening for internal malignancy in dermatomyositis: Data...
- Article: Coexisting myasthenia gravis, myositis, and polyneuropathy induced by ipilimumab and...
- Article: Polymyositis with elevated serum IgG4 levels and abundant IgG4+ plasma...
- 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