About Myositis


Myositis is a term referring to swelling of the muscles. According to the American Academy of Orthopaedic Surgeons, chronic myositis is a condition that occurs when the body’s immune system causes long-term inflammation of healthy muscles. No reason for this response is known. Myositis develops slowly and can be mild or debilitating. John Hopkins states myositis is not completely understood and patients do not always get better with the current treatment regimen. Several types of myositis exist, including general myositis, dermatomyositis, inclusion-body myositis, juvenile myositis and polymyositis.


The Myositis Association states myositis can be short term and caused by injury, infection and exercise. This type of swelling will typically resolve with little complications, while chronic myositis can be serious and lead to loss of muscle.


According to Johns Hopkins, dermatomyositis will initially begin with a rash and then progress to muscle weakness. The rash is a patchy bluish-purple and appears on the face, neck, shoulders, upper chest, elbows, knees, knuckles and back. Calcium deposits may develop under the skin, resulting in hard bumps. Johns Hopkins states muscle weakness is the most common symptom.

Inclusion-Body Myositis

Johns Hopkins describes inclusion-body myositis as a progressive weakness of muscle and muscle wasting. Patients will most often complain of difficulty swallowing, weak hands and decreased muscle tone in the arms and thighs. Inclusion-body myositis is two times more prevalent in men than women. According to Johns Hopkins, symptoms of inclusion-body myositis usually develop after age 50, although patients have reported symptoms as early as age 30.

Juvenile Myositis

Juvenile myositis is diagnosed in children under the age of 18. According to The Myositis Association, juvenile myositis is characterized by muscle weakness and a skin rash. The Myositis Association reports 3,000 to 5,000 children in the United States are affected by juvenile myositis. The other forms of myositis can affect children but is rare.


According to The Myositis Association, polymyositis usually weakens muscles in the neck, hip, back and shoulders. Polymyositis patients also complain of muscle pain, breathing difficulty and swallowing problems. The Myositis Association reports more women than men are affected. Polymyositis usually occurs after the age of 20.


According to The Myositis Association, diagnosing any form of myositis is complicated and takes time. Tests to determine a diagnosis of myositis may include measuring muscle enzymes in the blood, muscle and skin biopsies, MRIs, and antibody testing to determine the level of myositis-associated antibodies in the blood.


Treatment for all types of myositis vary according to the patient and his response to prescribed medication and therapy. According The Myositis Association, health care providers may use a combination of medications, such as steroids, immunosuppressants, immune boosters and enzymes, to treat symptoms of myositis. The American Academy of Orthopaedic Surgeons recommends exercise, physical therapy and rest to complement the medication regimen prescribed.

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