The American Rheumatism Association first listed psoriatic arthritis as a clinical illness in 1964. Approximately 5 to 8 percent of people with psoriasis also have psoriatic arthritis, with Caucasians showing higher incidence. The illness is a chronic, inflammatory, autoimmune arthritis that can involve any joint and the surrounding tissues. Both genetic and hereditary factors have a role in causing the disease.
General Symptoms
Onset of psoriatic arthritis usually occurs between the ages of 35 and 55, but the illness can strike at any age. Those affected have stiff, painfully swollen joints, usually accompanied by changes in the finger and toenails. Approximately one-third will develop eye symptoms, chiefly conjunctivitis. It is also characterized by periods of flareups and remissions. Symptoms and signs of psoriatic arthritis can follow several different, or sometimes overlapping patterns. According to the Johns Hopkins Arthritis Center, there are five types of clinical disease presentations.
Symmetric Type
Symptoms may be in the same fingers on each hand. Wrists, knees and elbows might also be affected in a symmetrical fashion. Nail manifestations are common, ranging from tiny pits in the nails to total flaking and crumbling of the entire nail and cuticle area.
Asymmetric Type
This is thought to be one of the most common forms, where only one, or a few small joints of the fingers and toes are involved. It can eventually lead to the fingers developing what is called a "sausage" appearance.
Distal Type
About 5 percent of people with psoriatic arthritis will show disease activity primarily in the joints of the fingers and toes closest to the nails. This is known as DIP, or distal interphalangeal predominant, psoriatic arthritis.
Axial Type
Axial arthritis refers to spinal involvement, called psoriatic spondylitis, and hip involvement, called sacroileitis.. According to the Spondylitis Association of America, approximately 20 percent of those with psoriatic arthritis will develop spinal inflammation, and will usually test positive for the genetic marker HLA-B27. Sometimes just the neck and lower spine are affected, but eventually the entire spine can become completely fused due to ongoing inflammation.
Arthritis Mutilans
Arthritis mutilans is another severe form of psoriatic arthritis that can cause total destruction of the joints of the fingers, and sometimes the feet. This is the least common type of psoriatic arthritis, occurring about 5 percent of the time. A clinical sign known as telescoping fingers can eventually appear wherein the fingers have undergone bone resorption.
