Psoriatic arthritis is a chronic inflammation of the joints that occurs in some
people with a chronic skin and nail condition known as psoriasis. Psoriasis
causes flare-ups of raised patches of skin covered with silvery scales. The
onset of psoriasis may occur at any age but is most commonly seen between the
ages of 15 and 50 years. Psoriatic arthritis can be noted before or after the
skin lesions appear.
What is going on in the body?
People with psoriasis may
develop arthritis that causes destruction of various joints. The lining of the
joint, the synovium, becomes inflamed. It reacts by producing extra synovial
fluid, resulting in a swollen joint. The smooth white surface of the joint, the
hyaline cartilage, can become thin, worn, and rough.
What are the causes and risks of the disease?
Psoriatic arthritis occurs only in people with underlying psoriasis. Psoriasis
occurs more often in people of European ancestry. Approximately 5% to 8% of
people with psoriasis will
develop this form of arthritis. It affects men and women equally.
While the exact cause of psoriatic arthritis is unknown, several factors are
suspected to be triggers for the disease. These factors include the following:
the person's immune system
Both psoriasis and psoriatic arthritis flare up in
people with HIV, the
immunodeficiency disorder associated with AIDS.