esp. males 15-40yrs
follows within 6 weeks (usually 1-3wks) of infection with Chlamydia trachomatis, Salmonella, Shigella, Yersinia, Campylobacter, HIV
thus, is usually associated with either a diarrhoeal illness or urethritis/cervicitis preceding it.
post-STD form: males 9x more likely than women
post-diarrhoeal form: woman as likely as men
women tend to have less severe disease than men
esp. knees, ankles, feet, heels (“lover's heel”) - usually asymmetric, symptoms usually last 3-12 months.
conjunctivitis, uveitis, oral ulcers, balanitis circinata, sausage-like digits, keratoderma blenorrhagica (waxy plaques on palms/soles), Achille's tendonitis, low back pain
80% have HLAB27 but only 20% of B27 +ve people will get a reactive arthritis following a trigger.