Synopsis
Recognise sterile inflammatory arthritis following gastrointestinal or genitourinary infection, exclude septic and crystal arthritis, treat active infection appropriately, and review persistent disease for a wider spondyloarthritis phenotype.
- Reactive arthritis usually begins days to several weeks after genitourinary or enteric infection and commonly causes asymmetric lower-limb oligoarthritis, enthesitis or dactylitis.
- Ask about diarrhoea, dysuria, discharge, pelvic symptoms, sexual exposure, conjunctivitis, uveitis, oral lesions, keratoderma and heel pain without relying on the obsolete complete triad.
- A trigger may have been mild or resolved; request infection tests according to timing, symptoms and sexual-health or public-health implications.
- Aspirate a hot effusion for culture and crystals because septic arthritis, gonococcal infection and gout remain critical alternatives.
- Treat confirmed active chlamydial or other infection according to current antimicrobial and partner-management guidance; antibiotics do not reliably cure established sterile arthritis after cleared enteric infection.
- NSAIDs are commonly used for articular symptoms when safe. Intra-articular corticosteroid may help a selected joint only after infection is excluded; peri-entheseal injection needs an experienced clinician and must not enter tendon substance, particularly at the Achilles tendon.
- Persistent peripheral arthritis warrants rheumatology reassessment. A conventional DMARD may be considered after infection is excluded, but evidence is limited and it should not be assumed to treat axial disease.
- Provide sexual-health counselling, notification and retesting as indicated, and review for a continuing axial or peripheral spondyloarthritis phenotype.
Key red flags
Eye pain, photophobia, redness or blurred vision requires same-day ophthalmology rather than treatment as uncomplicated conjunctivitis.
Migratory pain, tenosynovitis, sparse pustules and sexual exposure requires urgent multi-site microbiology and antimicrobial assessment.
Investigation priorities
Exclude septic and crystal arthritis in an acutely inflamed accessible joint.
Management branches
New lower-limb arthritis follows diarrhoea or genitourinary symptoms without haemodynamic instability.
- Take sexual, gastrointestinal and medicine history, examine joint, skin, eye and entheses, and aspirate any significantly hot effusion for culture and crystals.
- Request site-appropriate chlamydia and gonorrhoea NAAT and stool tests when indicated, while assessing sepsis and disseminated infection risk.
- Treat confirmed active infection through antimicrobial and partner pathways and use comorbidity-adjusted anti-inflammatory care for sterile symptoms.
Key medicines
NaproxenCommon adult dosing is 250–500 mg orally twice daily with food for a reviewed short course when clinically suitable.Assess GI ulcer or bleeding, renal, cardiovascular and anticoagulant risk; use the lowest effective dose for the shortest time with gastroprotection when indicated. Avoid from 20 weeks of pregnancy unless clinically necessary and do not use from 28 weeks; follow current MHRA and product advice.
Doxycycline for uncomplicated chlamydia100 mg orally twice daily for 7 days is the usual adult regimen, subject to current sexual-health guidance and patient factors.Doxycycline is contraindicated for routine treatment in pregnancy; the 2026 BASHH guideline permits it only when the full course finishes before 15 weeks and no suitable alternative exists. Check allergy, oesophageal irritation, photosensitivity and interactions; provide partner-notification and STI-screening support.