Causes

Psoriatic arthritis occurs when your body's immune system attacks healthy cells and tissue. The immune response causes inflammation in your joints as well as overproduction of skin cells.

It seems likely that both genetic and environmental factors play a role in this immune system response. Many people with psoriatic arthritis have a family history of either psoriasis or psoriatic arthritis. Researchers have discovered certain genetic markers that appear to be associated with psoriatic arthritis.

Physical trauma or something in the environment — such as a viral or bacterial infection — might trigger psoriatic arthritis in people with an inherited tendency.