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Reactive Arthritis

Written by Ada’s Medical Knowledge Team

Updated on

What is reactive arthritis?

Reactive arthritis (ReA) is a rare inflammatory disease of the joints that occurs in reaction to an infection occurring in another part of the body. It sometimes is referred to as Reiter’s syndrome, Reiter’s disease, or Reiter’s arthritis. However, these terms only describe a small group of people living with ReA. The condition tends to occur in young adults and more frequently in men than women.

Read more about arthritis

The initial infection is caused by certain groups of bacteria infecting the gastrointestinal or urinary system. After an interval that could last for days to weeks (typically), the arthritis occurs. In most cases, it only affects one or a few joints of the legs. The diagnosis depends on the typical symptoms, clinical findings, course of disease, and the exclusion of other causes for arthritis. Initial treatment consists of nonsteroidal anti-inflammatory drugs (NSAIDs). ReA can vary in severity and normally occurs as an isolated illness with no further problems and a good prognosis. However, some people may experience persistent symptoms. 1, 2, 3, 4, 5

If you think that you might have reactive arthritis, you can try using Ada to find out more about your symptoms.

What are the causes of reactive arthritis?

Reactive arthritis (ReA) is an inflammatory disease of the joints that occurs in reaction to an infection occurring in another part of the body. Typically, reactive arthritis is triggered either by bacteria causing a urinary tract infection or an STD, such as chlamydia, or by bacteria causing gastroenteritis, which is also known as food poisoning – such as campylobacter. The triggering infection may have been so mild that it went unnoticed.

ReA is not an infection of the joints, and the severity of the initial infection is not related to the severity of the ensuing arthritis.

It is not known why exactly these symptoms develop outside the areas of the body that were or are still infected. Reactive arthritis is thought to be an autoimmune disorder, in which the body produces antibodies attacking healthy tissue that causes inflammation. 3, 6, 4

Risk factors

Reactive arthritis (ReA) is always brought on by an infection elsewhere in the body. The most common infections to trigger reactive arthritis are: 3, 5



  • infection of the gut, commonly from food poisoning
  • certain groups of bacteria, such as shigella, salmonella, campylobacter, and yersinia

Chlamydia pneumoniae

  • bacteria – which can cause a lung infection

Other infections

  • including Group A streptococci, acute tuberculosis, and some viral infections.

It is not known exactly what predisposes a person to develop ReA in response to infection. Certain factors that are more common in people with the condition include being: 1, 3, 5, 6

  • aged roughly 20 to 40 years old
  • male
  • a carrier of the HLA-B27 gene
  • HIV positive.

What are the symptoms of reactive arthritis?

The symptoms of reactive arthritis (ReA) usually begin two to four weeks after the previous infection. They can range from mild to severe, often appear suddenly and tend to last for several months – fluctuating in severity during that time. Signs and symptoms normally stop within about six months. They can be separated in different groups and include: 1, 2, 3

Musculoskeletal symptoms:


  • acute-onset
  • only one or a few joints
  • asymmetric
  • often lower extremities, particularly the knees


  • an inflammation of the site where bone connects to ligaments, tendons, or other connective tissue
  • pain, swelling, and local tenderness
  • most commonly affecting the back of the heel or sole of the foot


  • swelling of the fingers – which look like sausages

Low back pain

Additional symptoms include:

  • itchy, red eyes, known as conjunctivitis
  • painful urination caused by a urinary tract infection
  • genital discharge caused by a sexually transmitted disease
  • diarrhea caused by gastroenteritis
  • painless mouth ulcers
  • scaly rash on the palms or soles of feet
  • nail changes
  • sore rash on end of the penis known as balanitis
  • possibly weight loss and fever

However, none of the symptoms above are specific to reactive arthritis. The combination of painful urination, conjunctivitis, and arthritis is sometimes called Reiter's syndrome. Only one out of three people living with reactive arthritis show all of these signs. 1

If you think that you might have reactive arthritis, you can try using Ada to find out more about your symptoms.

What is the diagnosis of reactive arthritis?

Diagnosis is generally done after a referral is made to a rheumatologist, which is a type of doctor specializing in inflammation and pain in the joints, muscles, or fibrous tissue. Unlike other types of arthritis, there is no specific test which can diagnose reactive arthritis. Instead, a rheumatologist must gather information to rule out other conditions and hone in on the cause of a patient’s symptoms. 1, 3, 7

The three cornerstones of diagnosis are: 3

  • typical musculoskeletal symptoms (see above)*
  • history of urethritis or diarrhea previous to arthritis (May not have been noticed. Only in every second person with ReA the underlying germ can be identified. This is therefore not required for making a diagnosis.)
  • other infections are possible as well, although less commonexclusion of other forms of arthritis
  • crucial for diagnosis.

In order to achieve this, the doctor will obtain the following information: 3, 8, 9, 4, 10


Physical exam

  • any swollen joints, swollen fingers and toes, and/or tender areas?
  • any skin or eye inflammation?
  • any symptoms of sexually transmitted infection? (see above)

laboratory tests Routine laboratory blood test to analyze the person’s blood for signs of acute inflammation or certain systemic conditions. This includes:

  • complete blood count
  • acute phase reactants (Erythrocyte sedimentation rate (ESR or sed rate), C-reactive protein (CRP))
  • renal and liver function

HLA-B27 testing as people who carry this gene are more likely to develop reactive arthritis. This gene can be detected with a blood test. However, only 30 to 50 percent of people with ReA have it, and it is not specific to ReA.

Serologic testing for rheumatoid arthritis

Analyzing the person’s blood for rheumatoid factor "Anti-cyclic citrullinated peptide antibody". This is only obtained in people with arthritis in multiple joints. These antibodies are usually absent in people with ReA.


  • drawing fluid from an affected joint with a needle
  • performed if the joint is swollen
  • detects if joint is infected by analyzing white blood cell count and identifying bacteria
  • can rule out septic arthritis

Tool cultures

  • analyzing the person’s stool for certain groups of bacteria
  • performed if the person has diarrhea

Urine sample

a) analyzing the person’s urine for signs of a urinary tract infection

b) analyzing the person’s first portion of the urine specimen. This is performed if:

  • an infection of Chlamydia trachomatis is suspected
  • The person doesn’t report diarrhea or symptoms typical of urinary tract infection or STD.

Vaginal swab will be performed if:

  • an infection of Chlamydia trachomatis is suspected
  • The woman doesn’t report diarrhea or symptoms typical of urinary tract infection or STD.

Medical imaging

  • x-rays of affected joints and entheses (connection between bone and soft tissue)
  • performed to detect changes in the joint
  • can be necessary in order to rule out other causes of joint pain, such as certain forms of arthritis and stress fractures

What is the best Treatment for reactive arthritis?

The treatment of reactive arthritis can vary depending on the underlying infection that triggered the condition in the first place. Also, the treatment can differ depending on the symptoms present and on how the affected person reacts to the initial medication. 1, 3, 4, 5

Treatment generally covers these three areas: 3

  1. treatment of the infection
  2. treatment of arthritis
  3. treatment of other symptoms.
  4. Treatment of the infection: 3, 5

For some people with ReA, it is necessary to take antibiotics to treat the underlying infection that triggered the condition.

This may apply if:

  • There is an ongoing urinary tract infection or STD (particularly if it’s caused by chlamydia)
  • There is an ongoing gastroenteritis that is caused by certain groups of bacteria
  • It affects an old person
  • It affects a person with a weakened immune system.

This does not apply if the underlying gastroenteritis

  • has passed
  • is mild
  • is caused by a virus.

It is generally not recommended to take any antibiotics if there is no clear reason to do so.

  1. Treatment of arthritis:

The treatment of the arthritis itself aims at reducing inflammation and suppressing the body’s autoimmune reaction. Two stages can be distinguished: 1, 3, 5

a) treating an acute ReAb) treating a chronic ReA

  • lasting six months or longer
  • not reacting to previous treatment efforts.

a) treating an acute ReA:

Fortunately, in most cases reactive arthritis will resolve by itself and does not result in any joint destruction. Therefore, the treatment goal is to relieve the symptoms.Initial treatment consists of:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs), such as Diclofenac (Blood count, as well as liver and kidney function, should be checked before and during treatment).
  • Glucocorticoids (which are either administered as a tablet or directly into the affected joint)
  • This is only required in people who did not react to NSAIDs.
  • Disease-modifying antirheumatic drugs (DMARDs) (These reduce inflammation and prevent any destruction to the joint.
  • This is only required in people who did not react to NSAIDs and Glucocorticoids.

b) treating a chronic ReA

If the ReA lasts six months or longer and has not reacted to previous treatment, it is considered to be chronic. A specialist will advise on how to proceed.

3) Treatment of other symptoms: 3, 5

People with ReA who show symptoms affecting their eyes, mouth, or skin may require further treatment. In these cases, a specialist should be consulted who will assess the severity and necessity for treatment.

Can reactive arthritis be prevented?

This depends on the underlying infection that triggered the reactive arthritis. If it’s a urinary tract infection or STD caused by chlamydia, antibiotic treatment of the acute infection can prevent ReA from developing.There is no evidence suggesting that ReA resulting from gastroenteritis or chronic ReA can be prevented by antibiotic treatment. 5

What is the prognosis for reactive arthritis?

The course of disease can differ from person to person. In about half of all people with ReA, the symptoms will resolve within six months. However, in some people, the condition may persist and become chronic. 3, 4For people who have the HLA-B27 gene, recurrence may occur. ref1

What are the complications of reactive arthritis?

In some patients, persistent arthritis can lead to joint damage. Consulting a specialist, particularly in cases of chronic disease, is highly recommended.

If you think that you might have reactive arthritis, you can try using Ada to find out more about your symptoms.