Psoriatic arthritis is a type of arthritis that can affect people who have psoriasis. Psoriasis is a skin condition that causes itchy, scaly patches on the skin. The patches may be red, purple or brown depending on your skin color. Most people get psoriasis first, sometimes years before symptoms of psoriatic arthritis start. The main symptoms of psoriatic arthritis are joint pain, stiffness and swelling. These symptoms can affect any joint in the body. The symptoms of this condition can vary ... Psoriatic arthritis is a chronic inflammatory arthritis that develops in at least 5% of patients with psoriasis. The association between psoriasis and arthritis was first made in the mid-19th century, but psoriatic arthritis was not clinically distinguished from rheumatoid arthritis (RA) until the 1960s. Psoriatic arthritis is a type of arthritis that only occurs in people with psoriasis. Learn more about the types and causes of psoriatic arthritis , and what you can do to reduce symptoms. Find out about psoriatic arthritis , including what the symptoms are, how it's treated, what causes it and when to get medical help.