Psoriatic Arthritis

Psoriatic Arthritis Overview

Psoriatic arthritis is a specific condition in which a person has both psoriasis and arthritis. Psoriasis is a common condition. A person with psoriasis generally has patches of raised red skin with scales. The affected skin looks different depending on the type of psoriasis the individual has. Arthritis is joint inflammation.
 
Psoriatic arthritis is an autoimmune disease, meaning that your cells and antibodies (part of your immune system) fight your own tissues. Rarely, a person can have psoriatic arthritis without having obvious psoriasis. Usually, the more severe the skin symptoms are, the greater the likelihood a person will have psoriatic arthritis. 

Severe psoriatic arthritis involving the finger joints.
 
Psoriasis affects 2.5% of white people in North America. It is less common in African American and Native American people. Psoriatic arthritis affects 5-8% of people with psoriasis. A recent survey by the National Psoriasis Foundation indicated that approximately 1 million people in the United States have psoriatic arthritis. Many people who have psoriasis may not know that they have psoriatic arthritis.
 
Males and females are equally likely to have psoriasis. For psoriatic arthritis, males are more likely to have the spondylitic form (in which the spine is affected), and females are more likely to have the rheumatoid form (in which many joints may be involved).
 
Psoriatic arthritis usually develops in people aged 35-55 years. However, it can develop in people of almost any age.

Psoriatic Arthritis Causes

The cause of psoriatic arthritis is not known. It may have a combination of genetic (family), environmental, and immune causes. About 40% of people with psoriasis or psoriatic arthritis have a close relative with the condition. Some cases of psoriasis may be linked to infections.