Let's begin with what osteoarthritis and rheumatoid arthritis have in common. Both cause joints to become painful and stiff. And both of these frustrating conditions can limit mobility, rob you of independence and lessen your quality of life.
However, osteoarthritis and rheumatoid arthritis are two very different conditions in other ways. Osteoarthritis seems to be brought on, at least in part, by wear and tear. Over time, protective tissue called cartilage in the joint withers away. That leaves bones scraping against bone, causing pain and other symptoms.
By contrast, rheumatoid arthritis occurs due to a glitch in the body's immune system. Normally, the immune system produces white blood cells to attack intruders such as bacteria and viruses. If you have rheumatoid arthritis, though, the immune system mistakenly sends white blood cells to invade and destroy tissue in the joints.
There are other differences between osteoarthritis and rheumatoid arthritis. The latter can affect body parts other than the joints, including the eyes, lungs, skin and blood vessels. Rheumatoid arthritis is also usually symmetrical; that is, if your right wrist is affected, your left wrist probably will be too.