- Clinical science
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.
- Postinfectious autoimmune disorder
To remember that Shigella, Chlamidia, Campylobacter, Yersinia, and Salmonella are the most common causes for reactive arthritis, think of “She Cherishes Cooking Yummy Salmon.”
- Latency period: 1–4 weeks
Oligoarthritis (sometimes polyarthritis) 
- Acute onset
- Often asymmetrical with a migratory character
- Occurs predominantly in the lower extremities
- Oligoarthritis (sometimes polyarthritis) 
- Extra‑articular symptoms
- Symptoms from preceding infection
Reactive arthritis is a clinical diagnosis that may be supported by diagnostic steps, but there is no confirmatory test. 
- Laboratory tests
Most common infection-associated differentials
|Differential diagnoses of infection-associated arthritis |
|Nongonococcal||Gonococcal (disseminated gonococcal infection)|
|Risk factors|| || |
|Onset|| || || || || |
|Distribution pattern|| || |
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