<prompt> Reactive ahritis is awChlamydiaYerseniaSalmonellaAll  <response>: Reactive ahritis previously known as Reiters disease is predominantly a disease of young men, with a male preponderance of 15 : 1. It is the most common cause of inflammatory ahritis in men aged 16-35 but may occur at any age. Between 1 and 2 of patients with non-specific urethritis seen at genitourinary medicine clinics have reactive ahritis. Following an epidemic of Shigella dysentery, 20 of HLA-B27-positive men developed reactive ahritis. Classic triad Non-specific urethritis Conjunctivitis 50 Reactive ahritis Additional extra-aicular features Circinate balanitis20-50 Keratodermablennorrhagica 15 Nail dystrophy Buccal erosions 10 Precipitated by Bacterial dysentery, mainly Salmonella, Shigella,Campylobacter or Yersinia Sexually acquired infection with Chlamydia REF:DAVIDSONS PRINCIPLES AND PRACTICE OF MEDICINE 22nd EDITION PAGE NO 1107 