2 subtypes:

• (1) genital form related to sexual activity

• (2) enteric form related to GI infection (e.g. salmonella, yersinia, shigella, campylobacter)

Syndrome comprises arthritis and conjunctivitis (with urethritis also in the sexually related form)

• M:F incidence is 20:1, mainly aged 16–35Y

• 60–90% of the genital and enteric forms of the disease are associated with HLA B27

• Osteochondritis dessicans occurs in young men but is associated with repeated minor trauma

• Reactive arthritis - Reiter's syndrome (NHS Choices)