• Clinical science

Reactive arthritis (Reiter syndrome)


Reactive arthritis, (formerly known as Reiter syndrome), is an autoimmune condition that occurs after a bacterial infection of the gastrointestinal or urinary tract. It is categorized as a seronegative spondyloarthritis because of its association with HLA-B27. Reactive arthritis primarily affects young men and usually presents with musculoskeletal or extra‑articular symptoms. The characteristic triad consists of arthritis, conjunctivitis, and urethritis. The diagnosis is based on clinical features such as patient history and physical examination; there are no specific tests for reactive arthritis. Treatment is primarily symptomatic and consists of the administration of NSAIDs, as most patients recover spontaneously.


Epidemiological data refers to the US, unless otherwise specified.


She Cherishes Cooking Yummy Salmon: Shigella, Chlamidia, Campylobacter, Yersinia, and Salmonella are the most common causes for reactive arthritis.

Clinical features

The classic triad of reactive arthritis consists of urethritis, conjunctivitis, and arthritis, but it manifests in only about a third of affected individuals.

Can't see (conjunctivitis), can't pee (urethritis), can't climb a tree (arthritis).


Reactive arthritis is a clinical diagnosis that may be supported by diagnostic steps, but there is no confirmatory test. [1][4]

Differential diagnoses

Most common infection-associated differentials

Differential diagnoses of infection-associated arthritis [5][3][6]
Condition Reactive arthritis Septic arthritis Lyme disease [7] Syphilitic arthritis
Nongonococcal Gonococcal (disseminated gonococcal infection)
Bacterial pathogen
Risk factors
  • High sexual activity
  • Unprotected sex
  • Men who have sex with men (MSM)
  • Women (4:1)
  • Frequent outdoor activities (e.g., hunters, farmers, hikers)
  • Acute
  • Acute
  • Variable [9]
  • Progressive
  • Progressive
Clinical features
  • Secondary syphilis
    • Syphilitic arthritis
    • Epiphysitis, Osteochondritis
    • Para-articular swelling
    • Bilateral intermittent hydrathrosis of the knee
Distribution pattern
  • Polyarthritis
    • Asymmetrical
    • Migratory
    • Lower body (especially knee)
  • Monoarthritis
  • Mostly knees, hip, wrists
  • Polyarthralgias (ADS)
    • Asymmetrical
    • Migratory
    • Large and small joints [10]
  • Monoarthritis (also oligoarthritis/polyarthritis)
  • Polyarthropathy
    • Asymmetrical
    • Migratory
    • Intermittent or persistent
    • Large joints (knee, elbow)


The differential diagnoses listed here are not exhaustive.


There is no curative treatment. The goal of treatment is to primarily control symptoms as the disease is usually selflimiting. Extraintestinal manifestations should be treated as necessary.


  • Resolves spontaneously within a year
  • High rate of recurrence
last updated 11/18/2020
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