What is arthritis?
Arthritis is the inflammation of one or more joints. Symptoms of arthritis include joint pain, swelling, stiffness, and redness. There are over 100 types of arthritis. Arthritis may be triggered by injury (such as a fracture) or infection (viral, bacterial, or fungal). It may be due to gradual wear and tear on the joints or result from an autoimmune disorder. A person may have more than one type of arthritis.
Arthritis affects both sexes and all ethnicities. Most types are more common in adults, but arthritis can occur at any age and can affect joints in many different parts of the body. Some specific types of arthritis include:
- Osteoarthritis – associated with the aging process, joint damage, and joint deterioration; it is the most common form of arthritis, affecting about 27 million people in the United States.
- Rheumatoid arthritis – an autoimmune disorder that affects about 1.3 million people in the U.S. About 2 to 3 times more women than men are affected.
- Juvenile rheumatoid arthritis – an autoimmune arthritis that occurs in children under the age of 16; it may affect one or more joints. It also may affect internal organs and can cause eye inflammation.
- Gout – affects about 2.1 million Americans, mostly men starting in their 40's and 50's; it is a disorder associated with excess uric acid that deposits needle-like crystals into affected joints, especially in the big toe.
- Septic arthritis – caused by an infection in a joint; it can result in serious joint damage in a short period of time.
- Ankylosing spondylitis – a form of arthritis that mainly affects the spine.
- Reactive arthritis – a form of arthritis that affects joints, eyes, the urethra, and sometimes skin and mucous membranes; it is so called because it normally occurs as a reaction to an infection somewhere in the body.
Laboratory tests can be useful in diagnosing these forms of arthritis and/or ruling out other conditions that may cause similar symptoms. For more detailed information on these, click on the linked condition name to go to that article.