By skyforbes 
Formerly known as Reiter’s syndrome, reactive arthritis occurs from a bacterial infection in the body, according to the American College of Rheumatology. An inflammatory reaction typically starts within two to four weeks after the infection and arthritis symptoms may come and go over several weeks to months, per the Arthritis Foundation, though it can be more severe and longer lasting. Reactive arthritis typically affects a few large joints, usually on one side of the body, notes Azar. You’ll also notice inflammation of tendons, ligaments, and muscle attached to the bone, and swelling in fingers or wrists. Other possible symptoms include urethritis or inflammation of the urinary tract, conjunctivitis or inflammation of the eyes, fever, rash, and mouth ulcers. The main symptoms of reactive arthritis tend to go away after a few months, though some people will have symptoms for up to a year and others may have long-term mild arthritis. Rheumatoid arthritis, by contrast, is chronic, though in rare cases, notes Johns Hopkins Medicine, reactive arthritis can become severe and chronic.
Additional reporting by Deborah Shapiro.