PsA is caused by an “attack” by the body’s own immune system on healthy tissues. This process results in inflammation of joints and overproduction of skin cells. The exact mechanisms behind this immune “attack” are unknown, but genetic and environmental factors likely play a role. It is common for people with PsA to have a family history of this condition, particularly among first-degree relatives (parents and siblings). Therefore, it is possible that people with an inherited predisposition may develop PsA following an environmental trigger.