ConditionBones, joints & muscles
Reactive Arthritis
Reactive arthritis is joint inflammation that develops 1 to 4 weeks after an infection elsewhere in the body, usually a gut infection (such as Salmonella or Campylobacter) or a sexually transmitted infection (chlamydia). It typically causes painful, swollen knees, ankles or feet, and may come with red eyes and burning urination. It was once called Reiter's syndrome. Most people recover within 3 to 12 months with anti-inflammatory treatment, though some have recurring or long-term symptoms.
Also called: Reiter's syndrome (outdated), post-infectious arthritis, postenteric arthritis, sexually acquired reactive arthritis
At a glance
- What it is
- Sterile joint inflammation triggered by an infection elsewhere, usually gut or genital.
- Triggers
- Chlamydia; Salmonella, Shigella, Campylobacter, Yersinia; occasionally C. difficile.
- Who
- Most often adults aged 20 to 40; HLA-B27 increases risk and severity.
- Symptoms
- Asymmetric arthritis of knees, ankles, feet; heel pain; sausage toes; red eyes; burning urination; rashes.
- Treatment
- NSAIDs, steroid injections, treating any ongoing infection; DMARDs for chronic cases.
When to get help
Call 911 or go to the ER
- A single hot, very swollen joint with high fever and feeling very unwell (rule out a joint infection)
See a doctor within a day or two
- A painful red eye with blurred vision or light sensitivity (possible uveitis)
- Severe joint swelling preventing walking
- Burning urination or genital discharge, so the infection and partners can be treated
Book a routine appointment
- New joint swelling or pain 1 to 4 weeks after diarrhea or a possible sexually transmitted infection
- Heel pain, swollen toes or fingers, or low back pain with stiffness
- Joint symptoms lasting more than 6 weeks
How reactive arthritis develops
After certain bacterial infections, the immune system reacts to bacterial fragments that reach the joints, causing inflammation even though there are no live bacteria in the joint. Genetic factors, especially the gene HLA-B27, make some people more prone and are linked to more severe and longer-lasting disease. Reactive arthritis belongs to the spondyloarthritis family, along with ankylosing spondylitis, psoriatic arthritis and IBD-related arthritis.
Triggers
| Type of infection | Bacteria |
|---|---|
| Sexually transmitted | Chlamydia trachomatis (most common in many countries) |
| Gut (food poisoning) | Salmonella, Shigella, Campylobacter, Yersinia, sometimes C. difficile |
The infection may have been mild or unnoticed. Only a small proportion of people with these infections develop reactive arthritis.
Symptoms
Symptoms begin about 1 to 4 weeks after the infection.
Joints
- pain and swelling in a few joints, often on one side, mainly the knees, ankles and feet
- enthesitis: pain where tendons attach to bone, especially the heel (Achilles tendon or sole)
- dactylitis: a whole toe or finger swollen like a sausage
- low back and buttock pain from the spine and sacroiliac joints
Eyes
- conjunctivitis: red, gritty eyes, often mild
- anterior uveitis: painful red eye, light sensitivity and blurred vision, which needs urgent treatment
Urinary and genital
- burning urination, increased frequency, discharge (urethritis) or cervicitis
- these can occur after gut triggers too
Skin and mouth
- painless mouth ulcers
- keratoderma blennorrhagicum: scaly, thickened patches on the soles and palms
- circinate balanitis: a painless rash on the penis
General
- fatigue, mild fever and weight loss
The old "classic triad" of arthritis, conjunctivitis and urethritis occurs in only a minority of patients.
Diagnosis
There is no single test. Doctors combine:
- history of a recent gut or genital infection
- examination of joints, tendons, eyes and skin
- tests for the trigger: urine or swab NAAT for chlamydia and gonorrhea; stool cultures if diarrhea is ongoing
- blood tests: CRP and ESR (inflammation), HLA-B27; rheumatoid factor is usually negative
- joint fluid aspiration to exclude septic arthritis and gout
- imaging: X-ray, ultrasound or MRI of joints and sacroiliac joints in persistent cases
Treatment
- NSAIDs (ibuprofen, naproxen) at anti-inflammatory doses as prescribed: first-line treatment
- corticosteroid injections into swollen joints or around inflamed tendons
- short courses of oral steroids for severe or widespread symptoms
- antibiotics for an active chlamydia infection (treat partners too). Antibiotics generally do not help the arthritis itself after gut infections
- disease-modifying drugs such as sulfasalazine or methotrexate for symptoms lasting more than 3 to 6 months
- TNF inhibitors for severe, persistent disease
- eye drops prescribed by an ophthalmologist for uveitis
- physical therapy, rest during flares, then gradual exercise to maintain joint mobility
Outlook
Most people recover within 3 to 12 months. Some have recurring episodes, and a minority, especially those with HLA-B27, develop chronic arthritis or spondyloarthritis.
Prevention
- food hygiene: cook meat and eggs thoroughly, wash hands, avoid unpasteurized milk
- safer sex and STI screening
- prompt treatment of chlamydia
Frequently asked questions
What is reactive arthritis?
It is joint inflammation that develops after an infection elsewhere in the body, typically a gut infection or chlamydia. The joints are inflamed but not infected. It often affects the knees, ankles and feet, and may involve the eyes and urinary tract.
What causes reactive arthritis?
It is triggered by bacteria such as Chlamydia, Salmonella, Shigella, Campylobacter and Yersinia. The immune system's response to these infections causes the joint inflammation. People with the HLA-B27 gene are more susceptible.
How long does reactive arthritis last?
Most cases resolve within 3 to 12 months. Some people have recurrent flares, and a minority develop long-term arthritis, especially those who carry HLA-B27.
How is reactive arthritis treated?
Treatment includes NSAIDs, steroid injections into swollen joints, antibiotics for any active chlamydia infection, and disease-modifying drugs such as sulfasalazine for persistent symptoms. Physical therapy helps maintain movement.
Sources
This guide was written from current patient and clinical guidance, including:
- American College of Rheumatology: Reactive arthritis
- MedlinePlus: Reactive arthritis
- NIAMS: Reactive arthritis
- Spondylitis Association of America: Reactive arthritis
- CDC: Sexually Transmitted Infections Treatment Guidelines (chlamydia)