Reactive arthritis (ReA)
Reactive arthritis (ReA) is an inflammatory condition that develops in response to an infection in another part of your body. Though inflammation of your joints (arthritis) is a defining feature of reactive arthritis, this condition can also be associated with inflammation in other parts of your body, such as your eyes (conjunctivitis), skin and the tube that carries urine away from your bladder (urethritis). Reiter's syndrome is a type of reactive arthritis that specifically refers to the classic triad of arthritis, conjunctivitis and urethritis. Not all people with reactive arthritis have the three conditions described by Hans Reiter in 1916.
Coming into contact with bacteria and developing an infection can trigger reactive arthritis. Most cases take one of two forms, urogenital or gastrointestinal. If the triggering infection originates in the penis, vagina, bladder or urethra, it's called urogenital (genitourinary) ReA, or uroarthritis. If your infection is the result of something that you eat or handle, such as raw meat that's carrying bacteria, your condition is called gastrointestinal (enteric) ReA, or enteroarthritis.
Reactive arthritis is among a group of disorders known as seronegative spondyloarthropathies. These conditions, which also include psoriatic arthritis and ankylosing spondylitis, can cause inflammation in the joints of the spine and legs and arms, and inflammation in other parts of the body.
For most people, signs and symptoms of reactive arthritis come and go, eventually disappearing within 12 months. Treatments involve therapies to manage your symptoms and to eliminate any underlying infection.
Signs and symptoms
The signs and symptoms of reactive arthritis generally start days to weeks after exposure to a triggering infection in susceptible people. Your signs and symptoms may come and go over a period of several weeks or months. In fact, reactive arthritis can go undetected for a long time, because your signs and symptoms may be mild.
Common signs and symptoms include:
Less common signs and symptoms include:
Signs and symptoms may last three to 12 months. However, many people can control their symptoms with treatment and return to their normal routine within two to six months of the onset of reactive arthritis.
As many as half of people redevelop symptoms after their initial condition disappears, though it's possible that relapses are the result of reinfection. Arthritis and back pain are the symptoms that reappear most often, but urogenital and eye inflammation also tend to recur.
Approximately 20 percent of people with reactive arthritis develop long-term (chronic) arthritis, though the arthritis often is mild. The severity of your initial symptoms isn't related to your risk of developing a chronic condition. However, you may develop a more severe case of reactive arthritis and be more likely to develop chronic reactive arthritis if you carry the HLA-B27 gene.
Reactive arthritis develops in reaction to an infection in another part of your body, often in your gastrointestinal or genitourinary tract. You may not be aware of the triggering infection because it may cause mild symptoms or none at all. The severity of your initial infection isn't related to the severity of your reactive arthritis.
Numerous bacteria can cause reactive arthritis. Some are transmitted sexually, such as neisseria, ureaplasma and chlamydia — the bacterium most often associated with reactive arthritis. You can also be exposed to bacteria by eating or handling food that hasn't been correctly prepared. Food-borne bacteria include salmonella, shigella, yersinia and campylobacter.
Reactive arthritis isn't contagious. However, the bacteria that cause it can pass from person to person, such as during sexual contact and food preparation. But only a few of the people who are exposed to these bacteria develop reactive arthritis.
Genetic factors appear to play a role in the development of reactive arthritis, because the majority of people with this condition also have the HLA-B27 gene. Carrying this gene may make you more susceptible to developing reactive arthritis after being exposed to a triggering bacterium.
Reactive arthritis occurs most frequently in men 20 to 40 years old. In fact, it's the most common form of arthritis in young men. Though women also can acquire reactive arthritis, they usually have milder symptoms.
Women and men are equally likely to develop reactive arthritis in reaction to food-borne infections. However, men are nine times as likely as women are to develop reactive arthritis in response to sexually transmitted bacteria.
Reactive arthritis may have a genetic component because about 80 percent of people with this condition also carry the HLA-B27 gene. Having this gene doesn't mean that you'll develop reactive arthritis, but it may increase your chances of developing reactive arthritis if you're exposed to specific bacteria. For example, about 8 percent of healthy Caucasians carry the HLA-B27 gene, but only a few of them develop reactive arthritis.
Researchers have identified several subtypes of the HLA-B27 gene, and the frequency of each subtype depends on the population and ethnic group in question. Most HLA-B27 subtypes are associated with ankylosing spondylitis, a type of inflammatory arthritis, but the mechanism as to how disease occurs is still under research.