the cause of psoriatic arthritis is currently unknown. a combination of genetic immune and environmental factors are likely involved. in patients with psoriatic arthritis who have arthritis of the spine a gene marker named hla-b27 is found in about 50% of cases. blood testing is now available to test for the hla-b27 gene. several other genes have also been found to be more common in patients with psoriatic arthritis. certain changes in the immune system may also be important in the development of psoriatic arthritis. for example the decline in the number of immune cells called helper t cells in people with aids may play a role in the development and progression of psoriasis in these patients. the importance of infectious agents and other environmental factors in the cause of psoriatic arthritis is being investigated by researchers.
what causes psoriatic arthritis?