Medical professionals do not yet fully understand the causes of psoriasis. However, they do know that the immune system has an active involvement in psoriatic conditions. The immune cells attack healthy joint tissue, causing inflammation, swelling, and pain.
Genetics may play a role in PsA. Psoriatic conditions tend to run in families. In fact, over 40% of people with PsA have a family member with the condition.
Some people without the characteristic skin involvement of psoriasis may still develop PsA.
Environmental factors may also play a role. Injury, infection, and exposure to environmental triggers can cause PsA to flare, especially in people with a family history of the condition.