Reactive arthritis is an inflammatory arthritis that appears days to weeks after an infection of the gut or urinary tract, such as Chlamydia, Salmonella or Shigella. It mostly affects young adults, often those with HLA-B27, and the joint is inflamed but not infected.
Key symptoms
- Painful swelling of a few large joints, often the knees and ankles
- Heel pain or a whole swollen toe or finger (dactylitis)
- Red, irritated eyes
- Burning with urination or discharge; recent diarrhea
What you find on exam
- Asymmetric arthritis of the legs
- Achilles or plantar fascia tenderness
- Conjunctivitis; look for uveitis
- Skin and mucosa: rash on palms and soles, mouth ulcers, penile lesions
Tests
- ESR and CRP raised
- Chlamydia and gonorrhea NAAT; stool culture if diarrhea
- Joint aspiration to rule out septic and crystal arthritis
- HLA-B27 can support the diagnosis
Treatment basics
- NSAIDs such as naproxen for joint pain
- Treat active Chlamydia with antibiotics, including partners
- Joint steroid injection once infection is excluded
- Sulfasalazine or methotrexate for chronic arthritis
Red flags
- Single hot joint with fever, treated as septic until proven otherwise
- Eye pain, light sensitivity or blurred vision
- Symptoms lasting over 6 months or spreading to the spine
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.