Psoriatic arthritis (PsA) is a type of inflammatory arthritis that is unique in that it can affect both the joints and the skin. Inflamed joints in arthritis can be swollen and painful while patches of inflamed skin called psoriasis can be itchy and scaly. PsA can also affect other parts of the body including tendons in the feet, knee, hips, or ribs. About 1 in every 3 people who have psoriasis on its own can eventually develop psoriatic arthritis.
PsA belongs to a family of diseases called the seronegative spondyloarthropathies. Other members of this family include ankylosing spondylitis, reactive arthritis and enteropathic arthritis.
PsA is an autoimmune disease, meaning that it occurs when the body’s immune system attacks its own healthy cells and tissues. The reason why it does this is not well understood. When the body’s immune system is “activated” in this way, it can make a person feel very tired, similar to when they have the flu.
PsA tends to run in families, which means that genetics likely is a big factor in terms of who gets PsA. If a person has family members who have PsA, they have a higher risk of getting it themselves.
People who get PsA usually start experiencing symptoms between 30 to 50 years of age.