Reactive arthritis (ReA) can be defined as the development of sterile inflammatory
arthritis as a sequel to remote
infection, often in the gastrointestinal or urogenital tract. Although no generally agreed-upon diagnostic criteria exist, the diagnosis is mainly clinical, and based on acute oligoarticular
arthritis of larger joints developing within 2-4 weeks of the preceding
infection. According to population-based studies, the annual incidence of ReA is 0.6-27/100,000. In addition to the typical clinical picture, the diagnosis of ReA relies on the diagnosis of the triggering
infection. Human leucocyte
antigen (HLA)-B27 should not be used as a diagnostic tool for a diagnosis of acute ReA. In the case of established ReA, prolonged treatment of Chlamydia-induced ReA may be of benefit, not only in the case of acute ReA but also in those with chronic ReA or
spondylarthropathy with evidence of persisting chlamydia
antigens in the body. In other forms of ReA, there is no confirmed evidence in favour of
antibiotic therapy to shorten the duration of acute
arthritis. The outcome and prognosis of ReA are best known for enteric ReA, whereas studies dealing with the long-term outcome of ReA attributable to Chlamydia trachomatis are lacking.