The majority of reactive arthritis cases are triggered by sexually transmitted infections, infections of the urethra, and gastrointestinal infections. Sometimes, reactive arthritis develops after a respiratory infection.
Sexually Transmitted and Urethra Infections
An infection that affects the vagina in women and the bladder and/or the urethra in men can lead to reactive arthritis. Doctors call these types of infections genitourinary, or urogenital, infections.
Chlamydia (kla-MID-e-a) is the sexually transmitted disease most commonly associated with reactive arthritis. It is caused by the bacterium called chlamydia trachomatis. A watery or pus-like discharge from the genitals is a hallmark symptom of chlamydia, though some people have no symptoms at all. (Patients who suspect chlamydia are advised to see a doctor immediately for diagnosis. Left untreated, chlamydia can lead to serious problems including infertility.)
An infection of the gastrointestinal tract can cause reactive arthritis. Doctors sometimes call this dysenteric reactive arthritis. People can become infected after eating food that was not properly washed, prepared, stored and/or refrigerated. They can also get an infection if they handle something that is infected with the bacteria and do not wash their hands before touching their mouth or nose.
Examples of intestinal infections that cause reactive arthritis include:
- Salmonella sp.
- Shigella flexnerii
- Yersinia enterocolitica
- Campylobacter jejuni
- Campylobacter lari
- Chlamydia psittaci
- Escherichia coli
- Clostridium difficile
One study estimated that about 9 in 1000 people who had a campylobacter infection got reactive arthritis.1 In the same study, the rates were about 12 in 1000 for Salmonella and Shigella infections. However, researchers note that these estimates may be low, because reactive arthritis is notoriously difficult to study and not all patients who experience joint pain after an infection report it to their doctor.
Respiratory Infections (Less Common)
Another type of chlamydia bacteria species, chlamydia pneumonia, causes a respiratory infection that can also lead to reactive arthritis.
Non-reactive Arthritis: Arthritis Caused by Infections
Reactive arthritis is sometimes confused with other infections that themselves cause joint pain and inflammation—in other words, joint pain that is experienced as a symptom of the original infection.
For example, the Chikungunya virus, which is most common in parts of Asia, Africa, and the Indian Ocean, can cause a fever, joint pain, and rash that last for months or even years.
Only a medical professional can definitively diagnose an infection.