Introduction
Reactive arthritis is joint inflammation developing days to weeks after infection elsewhere, commonly gastrointestinal or genitourinary. Classic triad includes arthritis, urethritis, and conjunctivitis though not all features present.
Organisms such as Chlamydia, Salmonella, Shigella, Campylobacter, and Yersinia trigger immune response affecting joints. HLA-B27 association increases risk.
Most cases resolve within months; some become chronic spondyloarthritis. NSAIDs are first-line; antibiotics treat active chlamydial infection not enteric-triggered arthritis routinely.
This page explains triggers, symptoms, diagnosis, and treatment of reactive arthritis.
Overview
Previously called Reiter syndrome when triad complete. Asymmetric oligoarthritis of lower limbs is typical.
Differentiate from septic arthritis requiring joint aspiration urgently.
- Arthritis after remote infection
- GI or STI triggers common
- Asymmetric lower limb joint involvement
- HLA-B27 linked susceptibility
- Conjunctivitis and urethritis may occur
- Usually self-limited over 3-12 months
What happens in the body
Cross-reactive immune response or persistent microbial antigens in synovium provoke inflammation after infection clears from primary site. Genetic susceptibility modulates severity and chronicity.
Synovial fluid usually sterile on culture in classic reactive arthritis.
- Post-infectious immune-mediated synovitis
- Molecular mimicry or persistent antigen hypothesis
- Enthesitis at tendon insertions common
- Mucocutaneous lesions keratoderma blennorrhagica rarely
- Chronic spondyloarthritis evolution in subset
Signs and symptoms
Musculoskeletal and extra-articular signs:
- Painful swollen knee, ankle, or toe joints asymmetrically
- Sausage digit dactylitis
- Heel pain from Achilles enthesitis
- Dysuria or urethral discharge if post-chlamydial
- Red painful eye in conjunctivitis or uveitis
- Low back pain if sacroiliitis develops
- Oral ulcers and rash on palms or soles occasionally
- Recent diarrhea or urethritis history preceding arthritis
Causes and risk factors
Preceding infections:
- Chlamydia trachomatis sexually acquired
- Salmonella, Shigella, Campylobacter gastroenteritis
- Yersinia enterocolitica
- Clostridioides difficile and other atypical triggers reported
- HLA-B27 positivity increases risk and chronicity
- Not direct joint infection in classic reactive arthritis
- Smoking may worsen spondyloarthritis outcome
Diagnosis and evaluation
Clinical syndrome after infection:
- Arthritis 1-4 weeks after dysentery or urethritis
- Joint aspiration to exclude septic arthritis: synovial WBC elevated, culture negative
- STI testing and stool culture if recent illness
- HLA-B27 optional not required for diagnosis
- C-reactive protein and ESR elevated
- Eye exam for uveitis if red eye
- Differentiate gonococcal arthritis which is septic
Treatment and management
Anti-inflammatory and treat active STI:
- NSAIDs first line for joint inflammation
- Single dose azithromycin or doxycycline partner-treated course for active chlamydia
- Antibiotics do not change course of post-enteric reactive arthritis routinely
- Intra-articular steroid injection for monoarthritis when infection excluded
- Sulfasalazine or methotrexate for persistent polyarthritis
- Topical or systemic treatment for uveitis by ophthalmology
- Physical therapy maintain mobility
- TNF inhibitors for chronic refractory spondyloarthritis phenotype
Prevention, self-care, and lifestyle
Not every condition is fully preventable, but the steps below may lower risk or recurrence:
- Safe sex practices and STI screening
- Food hygiene to prevent bacterial dysentery triggers
- No vaccine prevents all trigger organisms
Possible complications
Delay, missed care, or unsafe self-medication can raise the chance of complications in some cases:
- Chronic arthritis or ankylosing spondylitis-like disease
- Anterior uveitis threatening vision if untreated
- Aortic regurgitation rare long-term
- Persistent enthesitis and disability
When to see a doctor or seek emergency care
Seek prompt medical advice or emergency care if any of the following apply—it is safer not to wait and see:
- Hot swollen joint with fever exclude septic arthritis urgently
- Joint pain after recent diarrhea or STI
- Painful red eye with arthritis
- Symptoms beyond 6 months needing DMARD evaluation
Living with the condition
Most patients recover within months. Chronic spondyloarthritis requires rheumatology long-term care similar to ankylosing spondylitis.
Report eye redness promptly; uveitis needs rapid steroid treatment.
Frequently asked questions
Do I need antibiotics for joint pain after Salmonella?
Antibiotics treat active infection if still present but do not shorten post-enteric reactive arthritis once triggered.
Is reactive arthritis contagious?
Arthritis itself is not contagious; underlying STI may be and needs treatment.
Can it become permanent?
Some develop chronic spondyloarthritis; early rheumatology care improves outcomes.
Important caution
This article is general health education in English. It is not personal rheumatology advice.
Acutely hot monoarthritis with fever needs emergency joint aspiration to exclude sepsis.
Reactive arthritis usually resolves but requires STI treatment and monitoring for chronic joint and eye disease.