Reactive arthritis: is it a useful concept?

Reactive arthritis (ReA) is one of the most common arthritides affecting young adults. In most cases it follows urogenital or enteric bacterial infection, but its pathogenesis is not fully understood. It is generally considered a sterile arthritis which appears to involve immune response to bacterial organisms and genetic host susceptibility associated with the presence of HLA-B27 antigen. New findings suggest that in some ReA cases, viable bacteria are present inside the joints, and these organisms may cause the disease and trigger the inflammatory response. ReA manifests clinically as a rheumatoid factor negative oligoarthritis associated with enthesopathy and certain mucosal and skin lesions. Laboratory findings in ReA are non-specific. Although concepts of its pathogenesis are still evolving, so-called ReA remains an important condition to be distinguished from rheumatoid arthritis. Prognosis is generally better. Treatments with known effects in some cases include non-steroidal anti-inflammatory drugs, intra-articular corticosteroids, oral tetracyclines and sulphasalazine. The occasional chronic and severe ReA may be very difficult to treat.