Reactive arthritis

Reactive arthritis (ReA) is a sterile inflammatory arthritis that follows an infection at a different site, commonly enteric or urogenital. It is classified as a type of seronegative spondyloarthropathy.

ReA is formerly known as Reiter syndrome/disease, which is the combination of urethritis, arthritis and conjunctivitis. Not all patients with ReA have Reiter syndrome (also see History and etymology). 

ReA most commonly occurs in males between age 15-35 2. It has an incidence of ~1 in 100 after enteric infections. 

Usually transient following infection and involving one or two large joints. The classic triad consists of:

  • arthritis
  • conjunctivitis
  • urethritis (cervicitis in women) 

The following mnemonic can be used to remember the classic triad encountered in ReA: "Can't see, can't pee, can't climb a tree''.

In ReA there is joint inflammation, bone proliferation, periostitis, and enthesitis.


ReA occurs after infections including 5-8:

  • enteric: Yersinia, Salmonella, Shigella, Campylobacter and less commonly enterotoxic Escherichia coli (ETEC)
  • sexually-transmitted: Chlamydia trachomatis
  • other: brucellosis
  • HLA B27 positive in ~80% of patients

Distal lower extremity involvement (MTP >> calcaneus > ankle > knee) is more prevalent than upper extremity involvement. It affects hands, wrists, and feet with a distribution that is unilateral or bilateral and asymmetric (it becomes symmetric in later stages).

It can have a very similar appearance to psoriatic arthritis with the classic features of ill-defined erosions, enthesopathy, bone proliferation, early juxta-articular osteoporosis, uniform joint space loss and fusiform soft tissue swelling 2.  

Both psoriasis and reactive arthritis can cause a sacroiliitis, which is usually asymmetric 3.

The disease was originally named after Hans Reiter. However, recently this term has not been encouraged as he was a convicted Nazi war criminal who performed experiments of a new typhus vaccine that caused the death of hundreds of prisoners of war 9.

  • psoriatic arthritis
    • ReA has different distribution with hand involvement, which is common in psoriatic arthritis, very uncommon 2
    • spondyloarthropathy and sacroiliitis are identical in both conditions
  • disseminated gonococcal infection 
    • causes a septic arthritis c.f. sterile process of ReA
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Article Information

rID: 25753
Section: Syndromes
Tag: cases
Synonyms or Alternate Spellings:
  • Reiter's Disease
  • Reiter Disease
  • Reiter's syndrome
  • Reiter syndrome
  • Reactive arthritis (ReA)

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