Health Encyclopedia
Search Clinical Content Search Patient Health Library
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A-Z Listings

Myositis

Myositis means muscle inflammation. There are various forms of myositis. One form is polymyositis, which affects muscles throughout the body. Another is dermatomyositis, which affects both muscle and skin. Other body tissues can be affected as well. There are forms of myositis that are linked to inflammation in the lung.

Myositis is thought to be an immune system problem. Immune cells in the body are designed to attack and destroy invading viruses and harmful bacteria. In myositis, the immune system attacks the body's own tissues. Health experts don't know why this happens. Skin, muscle tissue, or both are often involved. Other parts of the body may also be affected. This includes the lungs. Myositis may be set off by exposure to certain chemicals, medicines, or viruses. But often a cause can't be found. This is known as idiopathic myositis.

The main symptom of myositis is muscle weakness or aching (especially large muscles such as those on the thighs, hips, shoulders, neck, and trunk). This can make it hard to climb stairs, get out of chairs, lift heavy things, or raise your arms over your head. The muscles in the throat can also be affected. This can lead to trouble swallowing. People with dermatomyositis often have skin changes. This may include a rash. Children may have different symptoms from adults.

People with myositis should be assessed for lung disease.

Some people have only mild symptoms that get better with treatment. But in many cases the disease is long-lasting (chronic). There are times when symptoms are worse (active disease). These may be followed by times when symptoms get better or go away (remission).

Treatment may include steroid medicines taken by mouth (oral). It may also include medicines that suppress the immune system. Rest, physical therapy, and exercise may help ease symptoms.

Home care

  • Take any prescribed medicines as advised.

  • Stay active. Exercise and physical activity help to keep your muscles in top shape. Talk with your doctor about an activity plan that's right for you.

  • If your muscles ache, rest as needed.

  • If advised, stay out of the sun. The sun can make a skin rash worse.

  • If you have trouble swallowing, talk with your doctor. They can make changes to your diet. This can help prevent breathing food into your lungs, which can lead to pneumonia and other problems.

  • Stay up to date on all provider visits. Get all your advised screening testing.

  • If you're disabled because of severe disease, talk to your employer. Work with them to make reasonable accommodations when needed.

Follow-up care

Follow up with your doctor as advised. You can find help at the sites below.

When to get medical advice

Contact your doctor right away if: 

  • You have a change in your bowel or bladder habits.

  • You see blood in your stool (black or red color).

  • You have unexpected weight loss.

  • You find a lump in your breast or elsewhere.

  • You breathe in food when eating (aspiration).

  • There's a change in the look of a wart or mole.

  • You have a lasting cough or hoarseness or you cough up blood.

  • You have night sweats or unexplained fevers.

  • You are short of breath.

  • Your muscle pain gets worse.

  • You have joint swelling.

  • Your symptoms get worse.

Online Medical Reviewer: Melinda Murray Ratini DO
Online Medical Reviewer: Rajadurai Samnishanth Researcher
Online Medical Reviewer: Raymond Kent Turley BSN MSN RN
Date Last Reviewed: 4/1/2025
© 2000-2025 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
Powered by Krames by WebMD Ignite

These resources and their content are provided by a third party for informational purposes and do not necessarily reflect the values and positions of Ascension, its ministries, or its subsidiaries.

About StayWell | Terms of Use | Privacy Policy | Disclaimer

The Services may integrate with Third-Party Apps or contain third-party content or provide links to third-party websites. For example, the Services may integrate with Third-Party App providers to provide you with information. You authorize Ascension to transmit information about You to and receive information about You from applicable third parties.
You agree that Ascension is not responsible for Third-Party Apps, third-party content or third-party websites, and does not make any endorsements, representations or warranties regarding the same. Your use thereof is at Your own risk and subject to the third party’s terms and conditions, as applicable. By using a Third-Party App or third-party content or websites, You agree to the applicable third party’s terms and conditions, even if Ascension does not present them to You at the time of Your use.