Reactive arthritis (ReA) is a rare type of arthritis that occurs after certain types of infections. It can affect joints of the lower body such as the feet, ankles, hips, knees and sometimes the lower back.
Reactive arthritis is usually acute (sudden onset, short-term), but it can also be chronic (long-term). Chronic forms can flare up and down. Reactive Arthritis used to be called Reiter’s syndrome.
Reactive Arthritis belongs to a family of diseases called the seronegative spondyloarthropathies. Other members of this family include ankylosing spondylitis, psoriatic arthritis, and enteropathic arthritis.
Who Gets Reactive Arthritis
Reactive arthritis typically occurs 10 to 14 days after an infection of the bowels (diarrhea), the urinary tract, or following a sexually transmitted infection (STI) such as chlamydia. For some reason that is not well understood, the infection triggers an arthritic reaction.
Reactive arthritis affects adult men and women aged 30 to 40. It is a bit more common in men. There is a genetic component in people who get Reactive Arthritis. About 75% of all patients who get it have a gene called HLA-B27.
Understanding Reactive Arthritis
Reactive Arthritis symptoms can be very typical of any inflammatory arthritic condition.
At the initial onset of the disease, people can feel unwell, tired and feverish. They may have headaches or lose weight. These early symptoms can also be caused by the recent infection triggers this form of arthritis.
The condition typically occurs 1 to 4 weeks after an infection of the bowels, urinary tract, or following a sexually transmitted infection (STI).
Reactive Arthritis tends to start very quickly and can be very intense. It most commonly affects joints in the feet, ankles, knees, and hips. They can become very stiff, swollen, painful, warm, and may be slightly red. The disease can also cause inflammation of the joints of the lower back leading to back pain and stiffness. Inflammation in the tendons is common as well.
Reactive Arthritis is often asymmetric, meaning it often affects just one side of the body.
In some cases, the toes can swell up like sausages (this is called dactylitis). In Reactive Arthritis, often only a single digit is affected. Changes to the nails might also occur.
Other conditions that can be present with Reactive Arthritis include inflammation of the eye (conjunctivitis) and genital or urinary symptoms such as painful urination (urethritis) or pelvic pain in women. Men can sometimes have genital sores.
In rare cases, a rash may occur on the skin and sores on the mouth or nose may develop.
There is no single diagnostic test for reactive arthritis. It is best diagnosed by a rheumatologist: a specialist who is very familiar with arthritic diseases. They will take a careful and complete history and will perform a thorough physical examination, and then will order tests to investigate further.
People who think they might have Reactive Arthritis should tell their doctor if they’ve recently had a bowel infection, urinary infection, or an STI.
One mnemonic, or memory aid, used by medical students to help them remember how to diagnose Reactive Arthritis is: can’t see, can’t pee, can’t climb a tree. These three features are common but they are not always all present. They describe how Reactive Arthritis can affect the eyes, feature genital and urinary symptoms or be associated with a recent infection, and feature arthritis symptoms that tend to focus on large joints. Doctors may investigate each of these features if they suspect a diagnosis of Reactive Arthritis.
Common Tests for Reactive Arthritis
Looking for inflammation: Reactive Arthritis is an inflammatory arthritis so these tests are expected to have abnormal results. Common tests for inflammation include the Complete Blood Count (CBC), Erythrocyte Sedimentation Rate (ESR), and the C-Reactive Protein (CRP) test.
Looking for a Genetic Marker: Over 75% of people with Reactive Arthritis will be positive for a gene called HLA-B27. However, as HLA-B27 is also present in about 6% of this population, so doctors and patients need to be careful interpreting the results of this test. A positive HLA-B27 test does not mean there is Reactive Arthritis. The result of this test must be taken in context of other test results.
Sexually Transmitted Infection (Blood and Urine Testing)
Blood tests and urine tests looking for sexually transmitted diseases: Since Reactive Arthritis is often associated with a recent infection, STI tests for Chlamydia, gonorrhea, syphilis, and HIV are commonly ordered.
Urine tests that look for signs of infection: Urinalysis and urine culture tests look for signs of infections of the urinary tract.
Stool culture test looking for signs of infection: A stool culture looks for the types of bacteria often associated with an infection in the bowels.
Reactive arthritis typically occurs after an infection of the bowels, urinary tract, or following a sexually transmitted infection. For some reason, the infection seems to trigger the immune system to begin attacking its own tissues, creating an arthritis reaction.
Oftentimes the trigger infection has been cured or is in remission (dormant) by the time a person experiences symptoms of Reactive Arthritis. The arthritis symptoms usually occur 1 to 4 weeks after the infection, most likely around the 2 week mark (10-14 days).
The most common triggers are intestinal infections that cause food poisoning and/or diarrhea such as Salmonella, Shigella, Campylobacter, Yersinia, and Clostridium difficile; and sexually transmitted infections such as chlamydia.
Scientists aren’t sure exactly why the immune system causes an arthritic reaction, but it seems that there is a genetic component to the disease. About 75% of people who get Reactive Arthritis have a gene called HLA-B27. This suggests that people with this gene have a genetic predisposition to developing the disease after an infection.
The first step in treating reactive arthritis is to treat the infection if it hasn’t already been cleared. Bowel and urinary tract infections are usually treated with antibiotics. Other types of medications may be required for sexually transmitted infections.
Medications for Treating Arthritis Symptoms in Reactive Arthritis
Corticosteroids (Prednisone, Cortisone)
For acute (sudden and severe) attacks of reactive arthritis, corticosteroids can be very effective to control inflammation and to reduce pain and swelling. These can be taken orally as pills (prednisone) or sometimes as cortisone injections directly into a joint.
Corticosteroids provide the quickest relief of any treatment. It can take up to 24 or 48 hours to feel the effects. The effects can last for a few days up to a few months, depending on the individual person and the joint.
Corticosteroid injections are usually limited to 2 or 3 in a single joint per year.
Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)
Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) can also reduce the inflammation of joints caused by acute reactive arthritis. They also help to reduce pain. They can take a little longer to work than corticosteroids.
Disease Modifying Anti-Rheumatic Drugs (DMARDs)
Anti-Tumor Necrosis Factor Biologics
Biologics directed against Tumor Necrosis Factor can be an extremely effective group of medications that help relieve the joint pain and stiffness caused by Reactive Arthritis that aren’t relieved by anti-inflammatory drugs or Disease Modifying Anti-Rheumatic Drugs.
A number of anti-TNF biologics are available including Humira (adalimumab), Cimzia (certolizumab), Remicade/Inflectra/Remsima (infliximab), Simponi (golimumab), and Enbrel/Brenzys/Erelzi (etanercept).
Medications for Treating Eye Symptoms in Reactive Arthritis
If a skin rash or oral ulcers are present, a topical (applied to the surface) steroid such as cortisone is used. Eye drops that contain cortisone are usually used to treat conjunctivitis.