What is psoriatic arthritis?
Psoriatic arthritis causes inflammation in and around the joints. It usually affects people who already have psoriasis, a skin condition that causes a red, scaly rash, especially on the elbows, knees, back, buttocks and scalp. However, some people develop the arthritic symptoms before the psoriasis, while others will never develop the skin condition.
Psoriasis can affect people of any age, both male and female, but psoriatic arthritis tends to affect more adults than young people.
People with psoriasis may also have other types of arthritis, such as osteoarthritis or rheumatoid arthritis, but these aren't linked to the psoriasis.