This article was last reviewed on
This article waslast modified on February 12, 2020.
What is arthritis?

Arthritis is a general term describing conditions that affect one or more joints and/or the tissues around joints. Classic symptoms of arthritis include joint pain, swelling, stiffness, and redness. However, there are over 100 types of arthritis with different signs and symptoms.

Arthritis may be due to gradual wear and tear on the joints or result from an autoimmune disorder. It may be triggered by injury (such as a fracture) or infection (viral, bacterial, or fungal). You 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 of the more common types of arthritis include:

  • Osteoarthritis (OA) – the most common form of arthritis, OA affects over 30 million adults in the United States. It is chronic, resulting from the breakdown of cartilage in the joints over time and is associated with the aging process and "wear and tear."
  • Rheumatoid arthritis (RA) – this is an autoimmune disorder that affects about 1.3 million people in the U.S. Nearly two to three times more women than men are affected by RA.
  • Juvenile rheumatoid arthritis (JRA) – also called juvenile idiopathic arthritis (JIA), this is the most common type of childhood arthritis. It is defined as at least 6 weeks of persistent arthritis in a child younger than 16 years of age.
  • Gout – associated with excess uric acid that deposits needle-like crystals into affected joints, especially in the big toe, causing sudden and severe pain; gout mainly affects men over the age of 30 and women after menopause.
  • Psoriatic arthritis – associated with the skin condition psoriasis and has features such as joint pain, stiffness and swelling in any part of the body
  • Septic arthritis – caused by an infection in a joint; it can result in serious joint damage in a short period of time if not treated promptly.
  • Ankylosing spondylitis – a chronic form of arthritis that mainly affects the spine, causing painful inflammation of the joints between the vertebrae in the spine and between the spine and pelvis
  • Reactive arthritis – a form of arthritis that affects typically the knees, ankles, and feet and is also associated with inflammation of the urethra and the eyes (conjunctivitis or uveitis); 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 links for the specific condition articles listed above.

View Sources

Sources Used in Current Review

Arthritis Foundation. About Arthritis. Available online at https://www.arthritis.org/health-wellness/detail?content=aboutarthritis. Accessed January 2020.

Centers for Disease Control and Prevention. Arthritis Basics. Available online at https://www.cdc.gov/arthritis/basics/index.html. Accessed January 2020.

National Institute of Arthritis and Musculoskeletal and Skin Diseases. Arthritis and Rheumatic Diseases. Available online at https://www.niams.nih.gov/health-topics/arthritis-and-rheumatic-diseases. Accessed January 2020.

Sources Used in Previous Reviews

(2009 August 26, Updated). National Institute on Aging. Arthritis Advice [On-line information]. Available online at http://www.niapublications.org/agepages/arthritis.asp.

Arthritis Foundation. Juvenile Rheumatoid Arthritis. Available online at http://www.arthritis.org/disease-center.php?disease_id=38&df=definition. Accessed October 2010.

Arthritis Foundation. Gout: Who is at risk? Available online at http://www.arthritis.org/disease-center.php?disease_id=42&df=whos_at_risk. Accessed May 2010.

(April 2009) National Institute on Arthritis, Musculoskeletal and Skin Diseases. Health Information: Rheumatoid Arthritis. Available online at http://www.niams.nih.gov/Health_Info/Rheumatic_Disease/default.asp#ra_2. Accessed October 2010.

(Revised May 2006) National Institute on Arthritis, Musculoskeletal and Skin Diseases. Health Information: Osteoarthritis. Available online at http://www.niams.nih.gov/Health_Info/Osteoarthritis/default.asp#2. Accessed October 2010.

MedlinePlus Medical Encyclopedia. Septic Arthritis. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000430.htm. Accessed October 2010.

Arthritis Foundation. Do I Have Arthritis? Available online at http://www.arthritistoday.org/about-arthritis/do-i-have-arthritis/do-you-have-arthritis.php. Accessed Sept 2013.

MayoClinic.com. Arthritis. Available online at http://www.mayoclinic.com/health/arthritis/DS01122. Accessed Sept 2013.

MayoClinic.com. Psoriatic arthritis. Available online at http://www.mayoclinic.com/health/psoriatic-arthritis/DS00476. Accessed Sept 2013.

MayoClinic.com. Juvenile Rheumatoid Arthritis. Available online at http://www.mayoclinic.com/health/juvenile-rheumatoid-arthritis/DS00018. Accessed Sept 2013.

Centers for Disease Control and Prevention. Arthritis Types. Available online at http://www.cdc.gov/arthritis/basics/types.htm. Accessed Sept 2013.

Centers for Disease Control and Prevention. Childhood Arthritis. Available online at http://www.cdc.gov/arthritis/basics/childhood.htm. Accessed Sept 2013.

National Library of Medicine. PubMed Health: Arthritis. Available online at http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002223/. Accessed Sept 2013.

Arthritis Foundation. Juvenile Arthritis. Available online at http://www.arthritis.org/conditions-treatments/disease-center/juvenile--arthritis/. Accessed Sept 2013.

Arthritis Foundation. Rheumatoid Arthritis. Available online at http://www.arthritis.org/conditions-treatments/disease-center/rheumatoid-arthritis/. Accessed Sept 2013.

Arthritis Foundation. Osteoarthritis. Available online at http://www.arthritis.org/conditions-treatments/disease-center/osteoarthritis/. Accessed Sept 2013.