About 1 in 20 individuals with psoriasis will develop arthritis along with the skin condition.
Psoriasis generally precedes the arthritis.
The disorder can be exhibited in a variety of ways. The arthritis is generally mild and involves only a few joints. In a few people, the disease is severe and usually affects the fingers and the spine. When the spine is affected, the symptoms are very much like those of ankylosing spondylitis . The cause of psoriatic arthritis is not known, but genetic factors may play a role.