What causes psoriatic arthritis?

No one knows the exact cause of psoriatic arthritis, however, scientists suspect that genetics have something to do with it. For example, a child born to parents with psoriatic arthritis has a greater chance of developing psoriatic arthritis than a child who is not. Also, in identical twins, if one twin has psoriatic arthritis, there is a 30-40% chance the other twin will have it too.

Researchers have also considered exposure to infection or changes in the environment as possible causes of psoriatic arthritis.