Dermatomyositis and polymyositis
Also known as: Idiopathic inflammatory myopathy, unspecified
General information only. Anpheros does not diagnose and does not recommend treatment. Talk to a doctor or pharmacist about your situation. In an emergency, call 112 (or your local emergency number).
In short
Myositis is the inflammation of the muscles used to move the body, which can be caused by an injury, infection, or autoimmune disease. Polymyositis causes muscle weakness, typically in the muscles closest to the trunk of the body, while dermatomyositis causes both muscle weakness and a skin rash. Other symptoms of myositis can include fatigue after walking or standing, tripping or falling, and trouble swallowing or breathing. Although there is no cure, symptoms are managed with treatments such as high doses of a corticosteroid, other medications, physical therapy, exercise, heat therapy, assistive devices, and rest.
Source: MedlinePlus, National Library of Medicine.
AI-generated summary of the sources cited on this page, checked automatically against them. Not reviewed by a clinician; not medical advice.
Codes
Description
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
Next to it in ICD-10
- M23Internal knee problems (including meniscus damage)
- M30Polyarteritis nodosa
- M32Systemic lupus erythematosus (lupus)
- M34Scleroderma
- M41Scoliosis
- M45Axial spondyloarthritis, unspecified
Neighbouring codes in the classification, not a medical link.
External resources
Questions
What is the ICD-10 code for Dermatomyositis and polymyositis?
M33 (WHO, International Classification of Diseases, 10th Revision).
What is the ICD-11 code for Dermatomyositis and polymyositis?
4A41.Z: Idiopathic inflammatory myopathy, unspecified (WHO, ICD-11 for Mortality and Morbidity Statistics).
Sources and attribution
- ICD-11 for Mortality and Morbidity Statistics, © World Health Organization, licensed under CC BY-ND 3.0 IGO.
- Names other than the official source titles: Anpheros translations and plain-language names, made with AI assistance and checked automatically; the source names are in English.
- Source: MedlinePlus, National Library of Medicine.
- ICD-10 codes and titles © World Health Organization. Source: WHO, International Classification of Diseases, 10th Revision (2019).
Anpheros Search catalog 2026.10.5, published 17 October 2026. About the data →
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