Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.
About Myositis
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.
It sits within Bones, Joints and Muscles.
The lead U.S. institute for this subject is the National Institute of Arthritis and Musculoskeletal and Skin Diseases.
When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.
Research on Myositis
433 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.
What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.
Research currently under way
- FAST for DM - Fatty Acid Supplementation Trial (FAST) for Dermatomyositis (DM)National Institute of Environmental Health Sciences (NIEHS)
- Biomarkers in Autoimmune Disease of Nervous SystemTongji Hospital
- BAFF CAR-T Cells (LMY-922) for Treatment of Refractory Autoimmune DiseaseLuminary Therapeutics
- A Study of AZD0120 in Autoimmune DiseasesAstraZeneca
- Descartes-08 for Children, Adolescents, and Young Adults With Autoimmune DisordersCartesian Therapeutics
- A Study to Investigate the Safety and Preliminary Efficacy of ALLO-329, an Allogeneic CAR T-cell Therapy, in Adults With Autoimmune DiseaseAllogene Therapeutics
Research already completed
- Environmental Risk Factors for Myositis in Military PersonnelNational Institute of Environmental Health Sciences (NIEHS)
- Studies of the Natural History and Pathogenesis of Autoimmune/Connective Tissue DiseasesNational Institute of Environmental Health Sciences (NIEHS)
- A Study to Investigate the Efficacy and Safety of Efgartigimod PH20 SC in Adult Participants With Active Idiopathic Inflammatory Myopathy.argenx
- Study of Families With Twins or Siblings Discordant for Rheumatic DisordersNational Institute of Environmental Health Sciences (NIEHS)
Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.
Where to read more
Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.
Start Here
- DermatomyositisGenetic and Rare Diseases Information Center
- Metabolic MyopathiesAmerican College of Rheumatology
Symptoms
- Dermatomyositis: Signs and SymptomsMuscular Dystrophy Association
Diagnosis and Tests
- ANA (Antinuclear Antibody) TestNational Library of Medicine
- Dermatomyositis: DiagnosisMuscular Dystrophy Association
- Electromyography (EMG) and Nerve Conduction StudiesNational Library of Medicine
- Inclusion-Body Myositis: DiagnosisMuscular Dystrophy Association
- Polymyositis: DiagnosisMuscular Dystrophy Association
Treatments and Therapies
- Dermatomysitis: Medical ManagementMuscular Dystrophy Association
- Polymyositis (PM): Medical ManagementMuscular Dystrophy Association
Genetics
- Idiopathic inflammatory myopathy: MedlinePlus GeneticsNational Library of Medicine
Clinical Trials
- ClinicalTrials.gov: DermatomyositisNational Institutes of Health
- ClinicalTrials.gov: MyositisNational Institutes of Health
- ClinicalTrials.gov: PolymyositisNational Institutes of Health
Medical subject headings
Clinicians and researchers index this subject under Myositis. These are the terms to use when searching medical literature.
This page is built from the MedlinePlus health topic record for Myositis, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.