Reactive arthritis is a form of inflammation that can cause swelling, pain, and discoloration in the feet, ankles, knees, and back.

The medical community considers reactive arthritis a form of spondyloarthritis. This is a general term for inflammatory diseases that attack the areas where ligaments and tendons connect muscles to bones and joints.

Doctors describe the condition occurs as reactive because it develops in response to infections in other parts of the body.

Common causes include sexually transmitted diseases (STIs), such as chlamydia, and intestinal infections from bacteria, such as Salmonella or Shigella. Although reactive arthritis is not contagious, the bacteria responsible for the infection that causes it can spread.

Inflammation is the primary symptom of reactive arthritis. A person will most commonly experience flare-ups in their joints, urogenital tract, skin, and eyes.

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The symptoms of reactive arthritis can take weeks to appear following an infection.

They may include:

  • sore and swollen toes, fingers, knees, ankles, and other joints
  • pain in the lower back and sacroiliac joints
  • pain in the heels due to enthesitis, which is inflammation at the insertion sites of tendons and ligaments
  • blurry vision
  • irritated eyes and photophobia
  • conjunctivitis or uveitis
  • urethritis, which is inflammation of the urinary tract
  • rashes or crusty sores on the hands, feet, and penis
  • frequent, painful urination

The symptoms may recur in some people, and, in rare cases, reactive arthritis can become a chronic disease.

Reactive arthritis is most prevalent among males aged 10–30 years.

A 2020 review stated that males are nine times more likely than females to develop reactive arthritis due to STIs. The STI chlamydia is a particularly common cause of reactive arthritis.

Eating contaminated or poorly handled food can also trigger inflammatory diseases of the digestive tract that result in reactive arthritis. The bacteria responsible include:

  • Salmonella
  • Shigella
  • Yersinia
  • Campylobacter

Males and females get reactive arthritis through digestive tract illnesses at about the same rate.

Reactive arthritis is common in people living with HIV. As a result, a doctor may wish to test for HIV in people showing new symptoms of reactive arthritis.

Reactive arthritis and COVID-19

In limited cases, individuals receiving treatment for COVID-19 have shown symptoms of reactive arthritis. Other case studies have reported on people presenting with reactive arthritis symptoms shortly after a SARS-CoV-2 infection. However, additional research is necessary to assess any potential links between COVID-19 and reactive arthritis.

Stay informed with live updates on the current COVID-19 outbreak and visit our coronavirus hub for more advice on prevention and treatment.

There are currently no specific laboratory tests for reactive arthritis. As a result, doctors will use a range of techniques to diagnosis the condition. These may include:

  • taking a medical history, including past and current symptoms
  • examining any inflamed areas, plus the pelvic area, genitals, eyes, and skin
  • inspecting the joints for swelling, inflammation, and range of motion
  • testing a sample of the blood for rheumatoid factor, antinuclear antibody, and red blood cell sedimentation rate
  • checking for the HLA-B27 gene, as research has shown that 60–80% of people with reactive arthritis test positive for this gene

As several infections cause reactive arthritis, doctors will often perform tests to diagnose or exclude underlying factors. These tests may include:

  • testing for chlamydia
  • analyzing tissue samples from the throat, urethra, and cervix for bacteria
  • checking urine and stool samples
  • studying the synovial fluid present in the joints
  • taking X-rays of the spine, pelvis, and joints

As reactive arthritis can be difficult to identify, less severe cases might go undiagnosed.

A person’s treatment plan will depend on their current observable symptoms, the underlying causes of reactive arthritis, and whether the condition is at an acute or chronic stage.

However, treatment plans will typically focus on:

  • curing the triggering infection with antibiotics
  • managing pain
  • treating any genital, eye, or skin issues

Seeking medical treatment for reactive arthritis can involve working with different specialists, including rheumatologists.

Other doctors that might form part of a person’s healthcare team include a gynecologist or urologist for genital or urinary issues, an ophthalmologist for eye complications, and a dermatologist for skin problems.

Nonsteroidal anti-inflammatory drugs (NSAIDs) will typically be the first-line treatment for people with acute reactive arthritis. NSAIDs help a person manage symptoms such as swelling and discomfort.

Learn more about NSAIDs here.

A doctor may also recommend the use of corticosteroids, which are powerful medications that can reduce inflammation. A healthcare professional may inject corticosteroids directly into the affected joint area, or a person may take them orally.

Other treatments for chronic reactive arthritis include:

  • disease-modifying anti-rheumatic drugs
  • TNF and other antibody treatments
  • biological agents

Engaging in plenty of physical activity can be of benefit to a person with arthritis.

Exercise will not prevent reactive arthritis, but it may help people with arthritis experience less pain due to flare-ups and have better joint health.

Preventing repeat infections that can trigger reactive arthritis is also important for self-care. People can use barrier methods, such as condoms, to reduce the risk of acquiring an STI, and they can store and cook food at recommended temperatures to stop the spread of foodborne bacteria.

A person may also be able to alleviate the pain of reactive arthritis attacks when they occur. The careful use of heating pads or ice — taking care to shield the skin from direct contact with either — can provide relief from pain and swelling. Minimizing the pressure on an affected joint may also help reduce pain and discomfort.

With proper treatment, most people with reactive arthritis can fully recover within 3–5 months of the initial symptoms appearing.

However, in cases of chronic reactive arthritis, these symptoms may last for up to a year. People may also experience a recurrence of symptoms after treatment. The Arthritis Foundation reports that 15–50% of individuals will develop symptoms of reactive arthritis again.

These symptoms may occur due to infection, and they can also result from the development of other types of arthritis. A 2016 follow-up study involving people who had previously received treatment for reactive arthritis reported that 44% developed spondyloarthritis, and 4% developed psoriatic arthritis later in life.

Reactive arthritis is a form of inflammation that can cause swelling and pain in the joints.

It occurs as a result of infections in other parts of the body, including some STIs. Treatment typically aims to resolve the infection that triggered the condition and help the person manage pain and other symptoms.

The outlook for people with reactive arthritis is generally good, although the symptoms can sometimes recur.