Reactive arthritis is known to be relatively common after certain infections, now including SARS-CoV-2, the virus that causes COVID-19.

Reactive arthritis is joint pain and inflammation triggered by an infection. It’s particularly common after bacterial infections of your gastrointestinal (GI) tract or genitourinary system, which includes your genitals and urinary system. It’s also been reported after SARS-CoV-2 infection.

It’s thought that reactive arthritis develops when the body overreacts to an infection and attacks healthy tissue in your joints. The exact reason it develops isn’t entirely clear, but it seems to be more common in people with the HLA-B27 gene.

Current evidence suggests that reactive arthritis may develop 1–4 weeks after SARS-CoV-2 infection, although it seems to be rare.

Read on to learn more about what we know about the connection between COVID-19 and reactive arthritis.

Reactive arthritis is an autoimmune condition that has been most associated with bacterial infections. It’s also been reported as a complication of some viral infections, such as:

Emerging evidence suggests that reactive arthritis may develop after SARS-CoV-2 infection in a small number of people. COVID-19 has also been associated with other autoimmune diseases, such as:

The underlying reason why the SARS-CoV-2 virus may trigger autoimmune conditions isn’t fully understood. It’s thought that the virus might cause temporary immunosuppression, which leads to an increase of molecules such as interleukins in your blood that are associated with the development of arthritis and other autoimmune diseases.

Current evidence

In a March 2023 review of studies, researchers summarized all of the current evidence linking reactive arthritis to COVID-19. Of the 8,704 studies the researchers analyzed, only 27 studies examining 54 people were deemed relevant or were published in one of the five languages understood by the researchers.

The average age of the 54 people in the study who developed reactive arthritis was 49.8 years, and most of these people had mild COVID-19. Arthritis developed 22.3 days after SARS-CoV-2 infection on average.

The researchers found low-quality evidence suggesting that SARS-CoV-2 infection can trigger reactive arthritis even in people who don’t show evidence of autoimmune arthritis on imaging scan.

The evidence was considered “low quality” because all the studies the researchers analyzed were case studies or series, which are more prone to bias than other types of studies.

Most people in the study had no history of:

Symptoms resolved within a few days with treatment in all 54 people. Only one person under the age of 18 was included in the study.

In a study from July 2023, researchers reported a 15-year-old girl who developed severe wrist pain that required surgery. According to the researchers, it was only the third reported case in the medical literature of somebody under 18 developing reactive arthritis after SARS-CoV-2 infection.

Reactive arthritis appears to be a rare but possible side effect of COVID-19 vaccination.

In a 2023 case series, researchers reported reactive arthritis developing in both ankles of 17 people shortly after receiving the Pfizer or Moderna vaccines.

Another case series reported three people who developed knee inflammation that was possibly linked to COVID-19 vaccination. All three people had symptom relief with nonsteroidal anti-inflammatories (NSAIDs) and glucocorticoids.

In a February 2023 case study, researchers reported a 24-year-old man who developed reactive arthritis in his knee after receiving the AstraZeneca vaccine. The researchers posed that an old knee injury might have predisposed him to arthritis, but many other cases have been reported in people with no injury history.

In a review of studies published in March 2023, researchers reported 45 people who developed joint symptoms shortly after COVID-19 vaccination. About two-thirds of people developed symptoms within 1 week, and 71.1% had symptoms in multiple joints.

Other infections linked to reactive arthritis

Reactive arthritis is particularly common after bacterial infections affecting your genitals, urinary tract, or GI tract. These infections include:

Reactive arthritis can cause symptoms similar to other types of arthritis. It most commonly affects your:

  • knees
  • feet
  • toes
  • hips
  • ankles

Symptoms include joint:

  • pain
  • stiffness
  • warmth
  • redness
  • swelling
  • loss of motion

Some people also develop:

  • pain when urinating
  • discharge from their genitals
  • eye symptoms such as:
    • redness
    • discharge
    • pink eye
    • pain

It’s recommended to contact a doctor if you develop unexplained joint pain, especially if you’ve had a recent infection in the previous month. There are many reasons why you might develop joint pain, but a doctor can help you determine the underlying cause.

In the March 2023 review of studies, researchers recommended NSAIDs as the first-line therapy for reactive arthritis caused by COVID-19. The 54 people in the study were treated for 5–42 days. The most common NSAIDs they received were:

Other treatment options include steroids such as prednisolone and methylprednisolone injected into your muscle or joint, and disease-modifying antirheumatic drugs (DMARDs) such as sulfasalazine.

Reactive arthritis seems to be a potential complication of SARS-CoV-2 infection and an extremely rare complication of COVID-19 vaccines. It’s thought to be caused by an overreaction of the immune system to the infection or vaccine.

Reactive arthritis can be treated with medications such as NSAIDs or steroids. Most people treated with medications in case studies seem to make a full recovery.