Psoriatic arthritis psoriatic arthritis, and affect them symmetrically. Involvement of the spinal joints is more suggestive of psoriatic arthritis than rheumatoid arthritis. Osteoarthritis shares certain clinical features with psoriatic arthritis such as its tendency to affect multiple distal joints in an asymmetric pattern. Unlike psoriatic arthritis, osteoarthritis does not typically involve inflammation of the sacroiliac joint. Psoriatic arthritis sometimes affects only one joint and is sometimes confused for gout or pseudogout when this happens. There are five main types of psoriatic arthritis: The underlying process in psoriatic arthritis is inflammation; therefore, treatments are directed at reducing and controlling inflammation. Milder cases of
Reactive arthritis trachomatis" is the most common cause of reactive arthritis following urethritis. "Ureaplasma" and "mycoplasma" are rare causes. There is some circumstantial evidence for other organisms causing the disease, but the details are unclear. Reactive arthritis 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 reactive arthritis 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. There are few clinical symptoms, but the