Objective: To study the incidence and presenting clinical and microbiological features in subgroups of reactive arthritides.
Methods: In a defined community and during a 2-year period, we studied prospectively patients between 18 and 60 years with onset of suspected reactive arthritis, primarily seen by general practitioners.
Results: Annual minimum incidence of Chlamydia induced arthritis (n = 25) was 4.6 and of arthritis triggered by enterobacteria (n = 27) 5.0/100,000 individuals between 18 and 60 years. Triggering infections were asymptomatic in 36 and 26%, respectively. Patients with self-limiting arthritis without identified triggering agents (n = 60, incidence 11.0/100,000) had a normal prevalence of HLA-B27 and a more heterogeneous pattern of arthritis.
Conclusion: Our epidemiological study confirms suggested high incidence rates of reactive arthritides. Reactive arthritides must be considered in early arthritis, even without symptoms of triggering infections.