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. Myositis causes muscle weakness, usually in the muscles closest to the trunk of your body.


There are two main subtypes.

  • Polymyositis
  • Dermatomyositis
  • It can occur in any person. Usually females are affected more. Dermatomayositis is mostly seen in children and females in between of 20-30 yrs of age. Myositis is usually seen after 50 yrs of age.
  • This is a rare disease usually developing in 10/1,000,000 population per year.

After disease control is achieved with medicines – Muscle strengthening exercises under guidance of physiotherapist helps to regain strength of muscles.

Many factors can lead to Myositis. They are distributed in four parts.

  • Infections [ Bacterial,viral ]
  • Drugs
  • Cancer:- Different types of cancer can present as Myositis.
  • Arthritis:- Polymyositis / Dermatomyositis
  • Patient’s immune system play major role in development of these diseases. Disturbance in immune system leads to abnormal white cells in immune system.
  • These cells attack muscles and skin. These cause swelling of muscle/skin followed by damage to it.

Muscle, joints, skin, lung, heart, food pipe can be involved.

In most of the patients symptoms develop slowly.

  • Body pains.
  • Weakness after mild work.
  • Joint pain and swelling.
  • Swelling around eyelids.
  • Rashes over face and hands.
  • Breathlessness, dry cough.
  • Difficulty in swallowing

Myositis is diagnosed by patient’s symptoms and examination done by doctors trained in these diseases.

Following investigations are done as per need to confirm the diagnosis and to find possible cause.

  • Muscle enzymes – CPK, LDH, SGOT, ALODASE
  • EMG – Electrophysiology of muscles.
  • IMAGING – USG, MRI can help in diagnosing muscle inflammation and swelling

X-Ray chest, HRCT Thorax for lung involvement

2D ECHO – for heart involvement

  • MUSCLE BIOPSY – For confirming diagnosis, to know subtype of disease.
  • Routine blood tests: Blood counts, kidney, liver functions before starting medicines and periodically later.
  • Screening for cancer, infection- In patients having symptoms suggestive of these diseases.
  • Steroids: Prednisolone -steroids are used for initially for rapid control of disease. After control of disease is achieved, it is tapered down slowly in 6 months and continued in lowest possible maintenance dose. It can be given injection form in serious conditions.
  • Methotraxate, Azathioprine, Mycophenolate: These drugs are called DMARDS – Disease modifying drugs. They are given for long term control of disease and prevent recurrence. It can take up to 6 months for its full effect.
  • Biologics {Rituximab}: These drugs are used for resistant disease where first line medicines are not effective. Rituximab reduces B type white cells and helps in bringing disease under control.
  • Iv Ig (Immunoglobulin): It is used in resistant disease where first line medicines are not effective or there is a threat to life. It rapidly brings disease under control. It is given as injections every monthly.

It is given for very long period. Many patients may need lifelong treatment.

Patients should take easily digestible foods. They should avoid fried, oily, spicy food.