What is rheumatoid arthritis (RA)?

Updated: Mar 05, 2021
  • Author: Howard R Smith, MD; Chief Editor: Herbert S Diamond, MD  more...
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Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease whose hallmark feature is a persistent symmetric polyarthritis (synovitis) that affects the hands and feet (see the image below). Any joint lined by a synovial membrane may be involved, however, and extra-articular involvement of organs such as the skin, heart, lungs, and eyes can be significant. RA is theorized to develop when a genetically susceptible individual experiences an external trigger (eg, cigarette smoking, infection, or trauma) that triggers an autoimmune reaction. 

Rheumatoid arthritis. Rheumatoid changes in the ha Rheumatoid arthritis. Rheumatoid changes in the hand. Photograph by David Effron MD, FACEP.

See Rheumatoid Arthritis: In and Out of the Joint, a Critical Images slideshow, to help identify the distinguishing features of RA as well as the signs of extra-articular manifestations of this disfiguring disease.

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