<unk>  is associated with the HLA-B27 gene on chromosome 6 and by the presence of enthesitis as the basic pathologic lesion and is triggered by a preceding infection. The most common triggering infection in the US is a genital infection with Chlamydia trachomatis. Other bacteria known to cause<unk>  which are more common worldwide are Ureaplasma urealyticum, Salmonella spp., Shigella spp., Yersinia spp., and Campylobacter spp. A bout of food poisoning or a gastrointestinal infection may also precede the disease (the last four genera of bacteria mentioned above are enteric bacteria). Shigella is the most common organism causing<unk>  following diarrhea. Chlamydia trachomatis is the most common cause of<unk>  following urethritis. Ureaplasma and mycoplasma are rare causes. There is some circumstantial evidence for other organisms causing the disease, but the details are unclear.<unk>  usually manifests about 1–3 weeks after a known infection. The mechanism of interaction between the infecting organism and the host is unknown. Synovial fluid cultures are negative, suggesting that<unk>  is caused either by an autoimmune response involving cross-reactivity of bacterial antigens with joint tissues or by bacterial antigens that have somehow become deposited in the joints.
Reactive arthritis
Behçet's disease
Rheumatoid arthritis
Septic arthritis
Psoriatic arthritis
Plantar fasciitis
Inflammatory arthritis
Rheumatism