About Myositis
What is myositis?
Myositis is a disease associated with inflammation of the muscles. It is often associated with severe muscle weakness. Myositis can also affect other organ systems including the skin, joints, lungs, heart and gastrointestinal system. It is a chronic disease and can last a long time. The most common forms of myositis are polymyositis, dermatomyositis and inclusion body myositis.
Myositis is an autoimmune disease. This means that the body’s immune system does not behave normally. Instead of only fighting infections such as bacteria and viruses, the body’s own immune system attacks itself. With myositis, the immune system may attack specific muscles resulting in muscle damage and destruction. The immune system may also attack other organs such as the lung, skin and joints.
What are some of the symptoms of myositis?
Myositis may have many symptoms. Common symptoms of myositis include:
- Muscle weakness
- Muscle pains
- Rashes
- Fatigue
- Weight loss
- Low-grade fevers
- Arthritis
- Color changes of hands and feet with cold exposure (Raynaud’s Phenomenon)
- Difficulty swallowing
- Heartburn
- Cough
- Shortness of breath
Who gets myositis?
Although myositis is a rare disease, people of all ages, races and ethnic backgrounds can get the disease. Inclusion body myositis is more common in men, while dermatomyositis and polymyositis are more common in women. Myositis often begins when people are teenagers or when they are older than 60.
What causes myositis?
The cause of myositis is not known. As mentioned above, we do know that myositis is an autoimmune disease. In myositis, autoimmunity leads to inflammation of specific muscles. This inflammation results in muscle damage and may lead to muscle cell death. Many different muscle groups may be involved in the disease ranging from muscles of the arms and legs to those of the respiratory and gastrointestinal systems. In addition, the abnormal immune response can lead to other problems including, damage to blood vessels, joints, lungs and the heart.
Are there any other complications or concerns?
Studies have shown that people with myositis have a higher risk of developing different types of cancer. The vast majority of people with myositis do not develop cancer. It is important to be aware of this association and perform age-appropriate cancer screenings.
This information has been approved by Aryeh Fischer, MD (April 2008).
