Psoriatic arthritis causes inflammation, pain, and swelling of joints in some people who have psoriasis. Other parts of the body may also be affected. For example, inflammation may also affect tendons and ligaments. The severity can vary from mild to severe. In some cases, affected joints become damaged which can cause disability. Arthritis means inflammation of the joints. Psoriasis is a common skin condition which typically causes patches (plaques) of red, scaly skin to develop. Psoriatic arthritis is a particular type of arthritis that develops in some people who also have psoriasis. In most cases, the arthritis develops after the psoriasis – most commonly within 10 years after the psoriasis first develops. However, in some cases the arthritis develops much later. In a small number of cases the arthritis develops first, sometimes months or even years before the psoriasis develops. Men and women are equally affected. Research continues to show a link between psoriasis and several other serious health conditions known as “comorbidities,” such as cardiovascular disease, diabetes and depression.Up to 30 percent of people with psoriasis also develop psoriatic arthritis, which causes pain, stiffness and swelling in and around the joints.Psoriatic arthritis can develop at any time, but it most commonly appears between the ages of 30 and 50..