Chlamydia-induced reactive arthritis: hidden in plain sight?

Reactive arthritis belongs to the group of arthritidies known as the spondyloarthritides. There are two main types of reactive arthritis: post-venereal and post-enteric. Chlamydia trachomatis is felt to be the most common cause of reactive arthritis, in general. Until recently, even the terminology for the condition itself was unclear as multiple eponyms and names have been associated with reactive arthritis. In recent years, a great deal has been learnt about the epidemiology, pathophysiology and treatment of reactive arthritis and Chlamydia-induced reactive arthritis, specifically. Prospective epidemiologic data suggest that Chlamydia-induced reactive arthritis is underdiagnosed. Other truths being actively revealed include data suggesting that the pathogen itself (i.e., Chlamydia) might play an equally important role, or perhaps even more important, than the host with disease susceptibility; asymptomatic chlamydial infections might be a common cause of ReA and the two variants of reactive arthritis might respond differently to treatment in spite of the congruent clinical presentation. However, much about this syndrome remains shrouded in mystery. Data covered in this review suggest that Chlamydia-induced reactive arthritis might be a common condition that clinicians fail to recognise. An emphasis is placed on disease awareness since viable treatment options are emerging.