Understanding Myositis: Symptoms, Causes, Diagnosis, Treatment

By Dr. Swetal Chouhan in Rheumatology

Aug 28 , 2023 | 2 min read


Myositis refers to a group of inflammatory muscle disorders characterised by muscle weakness and inflammation. There are many causes of muscle inflammation, including infections, drugs induced and autoimmune. In autoimmune causes, the immune system mistakenly attacks healthy muscle tissue. Myositis can affect people of all ages and is more common in women than men. There are several types of myositis, but the two most common ones are:

    • Dermatomyositis (DM): It involves both muscle inflammation and skin rash, primarily affecting the face, chest, knuckles, knees, and elbows.
    • Polymyositis (PM): It primarily targets the muscles, causing muscle weakness and inflammation without the characteristic skin rashes seen in dermatomyositis.

Symptoms of Myositis

The signs and symptoms of myositis depend on the specific type and severity of the condition. Common symptoms include:

  • Muscle weakness: Usually, the muscles closest to the trunk of the body, such as the thighs, hips, and shoulders, are affected first.
  • Muscle pain and tenderness: Patients may experience muscle soreness and pain, which can be persistent or intermittent.
  • Fatigue: Generalised fatigue and weakness are common due to muscle involvement.
  • Skin rashes: In cases of dermatomyositis, a distinctive rash may appear on the face, chest, or other body parts.
  • Difficulty swallowing: Dysphagia can occur when the muscles responsible for swallowing are affected.

Causes of Myositis

The exact cause of myositis remains unclear, but it is believed to be an autoimmune disorder where the immune system mistakenly targets healthy tissues. Other factors that may contribute to myositis development include:

  • Genetic predisposition
  • Environmental trigger
  • Medications


A comprehensive evaluation is necessary to diagnose myositis, which may involve the following:

  • Physical examination: The doctor will assess muscle weakness, skin rashes, and other associated symptoms.
  • Blood tests: Tests for muscle enzyme levels (e.g., creatine kinase), inflammatory markers, and autoantibodies are crucial in diagnosing myositis.
  • Electromyography (EMG): It measures the electrical activity of muscles and helps determine the extent of muscle damage.
  • Muscle biopsy: A small section of muscle tissue may be taken to examine for inflammation and other abnormalities.


Treatment of myositis aims to control inflammation, relieve symptoms, and improve muscle strength. Common approaches include:

  • Corticosteroids: Prednisone is often the first-line treatment, as it helps reduce inflammation and muscle damage.
  • Immunomodulatory drugs: For some patients, additional immunosuppressive medications may be prescribed to target the autoimmune response.
  • Physical therapy: Customised exercise programs can help improve muscle strength and function.
  • Supportive care: Symptomatic treatment and lifestyle modifications can enhance overall quality of life.

Myositis is a complex and potentially debilitating condition that requires timely diagnosis and appropriate management. If you or someone you know experiences muscle weakness, persistent pain, or skin rashes, it's essential to seek medical attention promptly.

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