HomeHealth A-ZMyositis: Types, Symptoms, Causes, Diagnosis and Treatment

Myositis: Types, Symptoms, Causes, Diagnosis and Treatment


Myositis is a disorder that signals the immune system to attack the muscle, causing inflammation of the muscles. There are different types of myositis, and depending on the type, the patient may find it challenging to move or use the affected muscles. It may also lead to infection, injury, medication, or autoimmune disease. The condition is incurable, but several treatment options can reduce the symptoms.

The blog explains myositis, its symptoms, causes, and treatment options. 

What is myositis?

When the immune system attacks the muscle, it causes chronic inflammation that occurs at frequent intervals. Over time, this inflammation makes the muscle progressively weaker, resulting in muscle pain.

It is a type of myopathy – a disease that affects the muscle. Based on the type of myositis, it affects different muscle groups, including the muscles in the arms and shoulders, legs and hips, and abdomen and spine. Sometimes, patients experience muscle weakness around the eyes, esophagus, and diaphragm. Myositis symptoms include muscle pain, fatigue, soreness, trouble swallowing, and difficulty breathing. These symptoms may appear rapidly or gradually over time. Certain types of myositis cause skin rashes. 

It is a rare disease that doctors find difficult to diagnose. Myositis  may be triggered due to infection, injury, autoimmune conditions, and drug side effects. It affects adults and children equally, except for one type of myositis. The treatment of myositis is based on the type of myositis. The doctors also recommend specific exercises such as stretching and physical movement to strengthen the muscles.  

What are the types of myositis?

Based on the symptoms and the location of the muscle inflammation, the doctor diagnoses the type of myositis. There are five different forms of myositis. They are as follows:

  1. Polymyositis: It affects several muscles simultaneously. Patients with polymyositis notice muscle weakness in the muscle nearest to the trunk of the body, spreading from there. Polymyositis develops gradually and affects adults. Women are two times more prone to developing polymyositis than men. Each case of polymyositis is different, and it is often found that patients also suffer from other autoimmune diseases. 
  2. Dermatomyositis is an easily diagnosable form of myositis due to the appearance of a purple rash similar to a heliotrope flower. Typically, the rash appears on the eyelids, face, chest, neck, back, and over the joints, such as knuckles, elbows, knees, and toes. It is one of the conditions that affect both muscle and the skin. The disease progresses quickly and therefore requires immediate medical intervention to avoid complications. Patients with dermatomyositis are also at an increased risk of developing certain cancers. 
  3. Inclusion body myositis: A degenerative muscle disease that typically affects individuals above 50 years. Patients with inclusion body myositis experience muscle weakness in the extremities, such as the hands and below the knees. Sometimes, it affects the throat muscles, leading to difficulty swallowing – nearly 30% of patients experience it. Studies believe that this form of myositis is genetic. 
  4. Juvenile dermatomyositis: When children experience dermatomyositis, it is called juvenile dermatomyositis. It occurs in children below the age of 18. Girls are at a higher risk of developing juvenile dermatomyositis than boys. Doctors easily distinguish it from other forms of myositis due to muscle weakness and skin rashes. 
  5. Toxic myositis: Doctors believe it is due to certain prescribed medications and illicit drugs. One of the many medications that may cause the condition is a cholesterol-lowering medication called statins.

What are the symptoms of myositis?

Different types of myositis have their distinctive symptoms. However, the common symptoms are as follows: 

  • Weakness in the muscle
  • Pain in the muscle and joint
  • Tiredness
  • Inflammation
  • Breathing and swallowing difficulties
  • Arrhythmia

Patients with polymyositis may experience difficulty performing regular movements, such as the following:

  • Standing up after sitting
  • Climbing stairs
  • Lifting 
  • Reaching over the head

Other symptoms also include the following:

  • Weakness and pain in the muscle
  • Troubled swallowing and breathing
  • Frequent falling
  • Difficulty standing from a seated position
  • Constant dry cough
  • Fatigue
  • Sudden onset of fever
  • Skin thickening on the hands

The symptoms of inclusion body myositis are as follows:

  • Difficulty using hands and fingers to perform precise and mundane tasks, such as buttoning a shirt or tying a shoelace.
  • Gripping small objects
  • Troubled walking or standing 
  • Swallowing
  • Frequently tripping, falling, and loss of balance
  • Difficulty in getting up from a seated position
  • Weakness in the muscle
  • Pain in the muscle and swallowing issues
  • Decreased deep tendon reflexes

The following are the symptoms of dermatomyositis:

  • Dry, scaly, or rough skin with rashes
  • Presence of lumps over the knuckles, elbows, and knees that are often raised and scaly and easily break out. These bumps are called Gottron’s papules or Gottron’s sign.
  • Difficult getting up from a seated position
  • Fatigue 
  • Weakness in the muscle present in the neck, hip, back, and shoulders
  • Troubled swallowing
  • Hoarse voice
  • Pain in the muscle and inflammation of the joint
  • Solidified lumps of calcium under the skin
  • Abnormalities in the nail bed
  • Weight loss
  • Arrhythmia 
  • Gastrointestinal ulcers

The symptoms of juvenile myositis are as follows:

  • The appearance of reddish-purple rash on the eyelids and joints. Sometimes these rashes appear similar to a heliotrope flower.
  • Fatigue
  • Moodiness or irritability
  • Stomach pains
  • Difficulties in motor functions, including trouble climbing stairs, standing from a seated position and getting dressed
  • Trouble reaching over, for example, shampooing or combing hair
  • Difficulty in lifting the head and swallowing
  • Weakness in the muscle and joint pain
  • Sudden onset of fever
  • Gottron’s papules
  • Swelling or redness of the skin around the fingernails
  • Solidification of calcium under the skin
  • Hoarse voice

Patients with toxic myositis present similar symptoms to other forms of myositis.

What causes myositis?

Experts are unaware of the cause of myositis. However, research believes health conditions and environmental factors trigger it. The following are some of the causes of myositis:

  • Inflammatory conditions: Underlying health conditions that cause inflammation throughout the body may also cause myositis. Autoimmune diseases, in which the immune system attacks the body, also cause myositis. Inflammatory conditions may develop into severe myositis, such as dermatomyositis, polymyositis, and inclusive body myositis. 
  • Infection: A viral infection is one of the most common causes of myositis. Not often, bacteria, fungi, and other organisms cause myositis. Common cold, flu, and HIV viruses are some of the viruses that may cause myositis.
  • Drugs: Several different medications and drugs may lead to temporary muscle damage. Inflammation in the muscles is often misdiagnosed as myopathy and not myositis. The following are the drugs that may cause myositis or myopathy:
  • Statins
  • Colchicine
  • Plaquenil
  • Alpha-interferon
  • Cocaine
  • Alcohol
  • Injury: Strenuous exercise may lead to muscle pain, inflammation, and weakness for a few hours or days after a workout. Inflammation of the muscles causes symptoms of myositis. Myositis is caused due to exercise or injury typically and always completely resolves with rest and recovery. 
  • Rhabdomyolysis: When muscle breaks down quickly, it causes rhabdomyolysis. The symptoms of rhabdomyolysis are muscle pain, weakness, and inflammation. Sometimes, the urine colour changes to dark brown or red colour.

Other environmental factors that include are as follows:

  • UV radiation
  • Smoking
  • Recreational drugs
  • Dietary supplements
  • Exposure to dust, gas, and fumes

When to seek medical help?

It is crucial to consult the doctor if a person presents any symptoms of myositis. The doctor may diagnose the type of myositis the patient is suffering from. However, a patient should immediately consult a healthcare provider if they experience any of the following:

  • Difficulty moving any body part
  • Troubled breathing or swallowing


How is myositis diagnosed?

Patients with myositis are often misdiagnosed as it is a rare disease. Another reason for misdiagnosis is due to the primary symptoms of muscle weakness and fatigue  – also noticed in other health conditions. A healthcare provider discusses the medical history, notes current symptoms, conducts a physical exam, and asks how particular movements may make the patient feel. The physician may recommend the following tests:

  • Blood tests: The blood test results may indicate high levels of muscle enzymes, such as creatine kinase. The presence of the enzymes may mean muscle inflammation. Blood tests may also test the presence of an antibody that indicate an autoimmune disease.
  • MRI scans: A high-powered magnet and computer scanner is used to create images of the muscle to identify the areas that are affected by myositis correctly. It also shows the gradual changes in the muscles over a period of time.
  • Electromyography (EMG): The doctor inserts needle electrodes into different muscles to check the response of the muscles. These electrodes transmit electrical signals and can identify muscles that are weak and damaged due to myositis.
  • Muscle biopsy: It is the most accurate test to diagnose and identify myositis. The healthcare provider identifies a weak muscle and makes a small incision to remove a small sample of the muscle tissue for testing. In most cases of myositis, it is the conclusive  test in diagnosing and identifying the condition. 

The doctors may also recommend other tests, such as:

  • Nerve conduction study
  • Blood tests to reveal CPK levels, antinuclear antibody, and antibody panel
  • Genetic testing

What are the treatment options for myositis?

At present, myositis is incurable. However, the healthcare provider may treat the symptoms to reduce the impact on the daily routine. The goal of any treatment options is to reduce the symptoms until there is little to no inflammation of the muscles. There are two treatment approaches, such as

Medical Treatment

The physician may prescribe medications using the following two medicines:

  • Corticosteroids, such as prednisone, and other immunosuppressants medicine that may reduce the attack on healthy tissues and improves skin rash. The doctor may monitor the patient’s improvement at frequent intervals throughout the treatment. Prednisone and dexamethasone are the most common corticosteroids prescribed by doctors for myositis. Methotrexate, azathioprine, and mycophenolate mofetil are widely prescribed immunosuppressive medications for patients with myositis. 
  • Anti-inflammatory medications and nonsteroidal anti-inflammatory medicines, including aspirin or ibuprofen, are recommended to patients to help with pain relief. 

Lifestyle Changes

The following lifestyle changes help in preventing the symptoms: 

  • Exercise: Doctors usually recommend physical therapy with medication. Once the medicines take effect, regular stretching exercises help preserve the range of motion in weakened arms and legs and prevent muscle shortening. Doctors may also add whirlpool baths, heat, and gentle massage.
  • Rest: Ensuring the patient gets enough rest is crucial for managing myositis. Taking frequent breaks during the day is also required, and limiting activity is essential. 
  • Nutritious meal: A healthy meal is beneficial in preventing and limiting the effects of the symptoms. Therefore, following a dietician-recommended meal plan is essential. 
  • Reduce stress: Exercises such as yoga and meditation may help patients with myositis reduce stress, as it is crucial for patients to reduce  stress f. 

There are different options for inclusive body myositis and infectious myositis. Alemtuzumab may be an effective treatment option if a person suffers from inclusion body myositis, as inclusive body myositis is resistant to corticosteroid and immunosuppressive medicines. In the case of infectious myositis, some patients respond to oral antibiotics, such as cloxacillin, while others may require intravenous antibiotics and secondary treatment, such as draining abscesses. Failure to receive treatment may result in sepsis.


Myositis is a rare, incurable disease. However, several studies are being conducted to find a cause and a cure. With timely diagnosis, effective treatments, and regular follow-up, patients may be able to control the symptoms, to lead a normal life.

Frequently Asked Questions (FAQs)

Is myositis preventable?

Myositis is unfortunately not preventable as experts are unaware of the cause of the disease. However, when a patient notices symptoms, treatment options may help reduce the severity of the symptoms. 

Can a patient experience complete or partial remission?

With various treatment options, there is a likely chance that a patient may experience complete or partial remission of the disease.

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