Symptoms, Treatments, Causes, and More

“Myositis” is a term that refers to inflamed muscles. People often use it when referring to autoimmune conditions characterizable by muscle inflammation.

Myositis is muscle inflammation that can cause prolonged muscle fatigue and weakness. The two most common types of myositis are polymyositis and dermatomyositis.

Read on to learn more about the types of myositis, some possible causes of muscle inflammation, and what treatments are available.


What are the types of myositis?

Laura Stolfi/Stocksy United

Myositis is a type of inflammatory myopathy, and there are various types of myositis. These include:

  • Inclusion body myositis (IBM): IBM is characterizable as chronic and progressive muscle weakness and inflammation. It happens gradually over months or years, and early symptoms typically include tripping and falling.
  • Dermatomyositis: Anyone can have dermatomyositis, but it is more likely to affect females. Muscle follows a rash that weakness can appear on the:
    • eyelids
    • nose
    • cheeks
    • back
    • upper chest
    • elbows
    • knuckles
    • knees
  • Polymyositis: People over the age of 20 years are most likely to have polymyositis, and it affects females more than males. Muscle weakness begins gradually and worsens over time, and it typically affects the neck, hips, back, and shoulders.
  • Necrotizing myopathy: Necrotizing myopathy is a type of myositis characterizable by necrosis, or muscle cell death. In the past, medical professionals classed it as a type of polymyositis. It is also called necrotizing autoimmune myopathy and immune-mediated necrotizing myopathy.
  • Juvenile myositis: Juvenile myositis affects people under the age of 18 years. It is characterizable by muscle weakness in the back, neck, shoulders, and torso. If there is a patchy skin rash, this is known as juvenile dermatomyositis.

Muscle weakness can occur when the immune system mistakenly attacks or causes injury to healthy muscle tissues. Medical professionals do not know exactly what causes myositis to develop in most people.

Possible causes include:

  • an allergic reaction to a medication or toxic substance
  • exposure to a virus
  • an infection
  • other autoimmune conditions

What are the symptoms of myositis?

Symptoms of myositis in general include:

  • slow and progressive muscle weakness
  • fatigue, especially after walking or standing
  • tripping
  • falling
  • Difficulty swallowing
  • breathing difficulties

You may also experience different symptoms depending on the type of myositis you have.

Symptoms of polymyositis include difficulties with:

  • speaking
  • swallowing
  • standing up
  • reaching overhead
  • climbing stairs
  • lifting objects

If you have polymyositis, you may also experience:

Symptoms of dermatomyositis

Dermatomyositis is characterizable by a rash on the eyelids and on muscles that extend or straighten joints. These include the:

  • knuckles
  • toes
  • elbows
  • knees
  • face
  • neck
  • shoulders
  • upper chest
  • back

You may also experience:

  • swelling
  • weight loss
  • low-grade fever
  • sensitivity to light
  • calcinosis, or calcium deposits

Symptoms of inclusion body myositis

Symptoms of IBM happen gradually over months or years, and they typically occur in people ages 50 years or over.

Slow and progressive muscle weakness usually affects the thighs and forearms, and it usually affects both sides of the body. In some cases, however, it may only affect one side of the body.

The first noticeable symptoms of IBM are usually falls and trips. Other symptoms that follow include:

  • weakness in the fingers and wrists
  • Difficulty pinching and grabbing objects
  • Difficulty swallowing, which occurs in around 50% of IBM cases

Symptoms of necrotizing autoimmune myopathy

Symptoms of necrotizing autoimmune myopathy are similar to those of polymyositis and dermatomyositis. These include:

  • upper and lower body weakness
  • Difficulty standing up from low chairs
  • Difficulty climbing stairs or lifting objects
  • fatigue
  • weight loss
  • muscular pain

Symptoms of necrotizing autoimmune myopathy can be more sudden and severe, worsening over a period of days or weeks.

Symptoms of childhood inflammatory myopathies

Symptoms of childhood inflammatory myopathies typically affect people ages 2–15 years. Symptoms can include:

  • muscle and inflammation in the trunk weakness area
  • edema, or swelling
  • muscular pain
  • fatigue
  • rash
  • abdominal pain
  • fever
  • contracts
  • Difficulty swallowing and breathing

Around 20-40% of children with juvenile dermatomyositis experience calcinosis, which occurs when calcium deposits on the soft tissue. This can result in:

  • muscle weakness
  • muscular pain
  • joint contracture
  • skin ulcers
  • decreased muscle mass

What are the treatments for myositis?

As there are different types of myositis, treatment methods can vary. Generally, treatments for myositis include:

Medications for the treatment of myositis symptoms include:

  • corticosteroids, such as:
  • immunosuppressants, such as:
    • methotrexate
    • mycophenolate mofetil
    • cyclosporins
    • azathioprines
    • tacrolimus
    • cyclophosphamide
    • hydroxychloroquine

Your doctor may refer you to a physical therapist. Exercise and physical therapy can help with:

  • inflammation
  • fatigue
  • increasing stamina
  • building muscles

If you experience myositis, contact your doctor before starting any new exercise regimen.

Some people find that complementary and alternative therapies help alleviate some myositis symptoms. However, it is important to note that complementary therapies will not work for everybody, and you should seek the advice of a medical professional before starting any kind of complementary therapy in case it can have an adverse effect on your condition.

Complementary and alternative therapies include:

  • acupuncture
  • Ayurvedic medicine
  • traditional Chinese medicine
  • naturopathy
  • homeopathy
  • massage
  • yoga
  • breathing and other relaxation techniques
  • meditation
  • tai chi
  • reiki
  • hypnotherapy

Contact your doctor for advice before the beginning of any kind of complementary or alternative therapy. More research into this topic is needed to confirm whether or not complementary therapy is useful for myositis.

Contact your doctor as soon as you notice any symptoms of myositis. Early symptoms include experiencing trips and falls. In some cases, such as with dermatomyositis, you may notice a rash before you experience muscle weakness.

Your doctor will be able to carry out a physical examination and various tests to determine the cause of your symptoms.

How is myositis diagnosed?

To diagnose myositis, your doctor will evaluate your medical history and carry out a physical examination. They will also arrange for various tests and exams to help with diagnosing the underlying cause of your symptoms.

These can include:

  • blood tests to check for elevated levels of certain muscle enzymes and autoantibodies
  • electromyography to assess the electrical activity the muscles generate when resting and contracted
  • ultrasound to check for inflamed muscles
  • MRI to identify any visible anomalies in the muscles
  • muscle tissue biopsy to test for:
    • chronic inflammation
    • muscle fiber death
    • vascular deformities
  • skin biopsy to identify changes in skin that could suggest dermatomyositis

The types of tests your doctor arranges may depend on other symptoms you have.

What are the risk factors for myositis?

Although some potential risk factors, such as environmental factors, need further study to determine how much they contribute to the development of myositis, researchers have been able to identify certain factors that may increase your risk of myositis.

Possible risk factors for myositis include:

  • genetic factors, such as the presence of HLA 8.1 ancestral haplotype
  • exposure to viruses or bacteria
  • UV rays
  • smoking
  • dietary supplements
  • biological drugs
  • other autoimmune conditions, such as:

Contact your doctor if you have concerns about any possible risk factors for myositis.

Are there any complications of myositis?

If you do not receive treatment for myositis, or if treatment is not effective, you may experience complications.

Possible complications of myositis include:

  • breathing difficulties
  • Difficulty swallowing
  • scarring of the lungs if there is inflammation in the lungs
  • weakening of the heart, in rare cases

Myositis is inflammation of the muscles. There are various types of myositis that can affect different people, but generally, it can affect anybody of any age.

Depending on the type of myositis you have, tripping and falling may be the first symptoms, or you may notice a rash appearing before you experience weakened muscles. Your doctor will conduct a physical examination, laboratory analyses, and diagnostic tests to help determine the cause or type of myositis.

Contact your doctor if you experience any symptoms of myositis. They will be able to prescribe medication and refer you to a physical therapist.


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