Psoriatic arthritis, which was first described as a clinical disease in 1964, is a recurring condition of inflammatory arthritis that occurs in persons with the autoimmune skin condition psoriasis. Psoriatic arthritis affects both the joints and their surrounding tissues, including fingernails and toenails.
Who Is Affected?
In North America, psoriatic arthritis is reported to affect about 1 million adults or 2.5 percent of the white population, occurring in about 5-8 percent of all patients with psoriasis. It’s less prevalent among African Americans and Native Americans. Psoriatic arthritis affects 5-8% of patients with psoriasis. Psoriatic arthritis represents about half the incidence of rheumatoid arthritis.
The primary age of onset is 35-55 years, although people of any age can be affected. Males and females are affected equally.
Symptoms
Psoriatic arthritis primarily involves the small joints of the fingers and toes. In up to 80 percent of patients the fingernails and toenails may also be involved, and small holes or pits tend to appear in the nails. Unlike rheumatoid arthritis, psoriatic arthritis occurs asymmetrically, meaning that it does not affect the joints on both sides of the body evenly. Psoriatic arthritis may also manifest as arthritis mutilans, a very deforming and destructive form of arthritis.
Psoriatic arthritis affects the ligaments, tendons, fascia and joints, and it tends to be more severe in patients with greater skin involvement, especially when pustular psoriasis may be present. The skin is usually affected first, often preceding the development of arthritis by as long as twenty years. Occasionally, patients with psoriatic arthritis show no detectable signs of psoriasis although a careful history shows that there may have been evidence of scalp or nail lesions or a family history of psoriasis.
Psoriatic arthritis usually affects the joints and tissues of the hands and feet causing a condition of dactylitis, or a sausage-like appearance of the digits. The distal interphalangeal joints of the fingers and toes may be affected along with the extending nail. In patients who develop arthritis mutilans, the joint may appear to be dissolved causing an excess of overlying skin, causing an “opera-glass hand” appearance, which is more common in men than in women and occurs more frequently in early-onset disease. The upper cervical spine tends to be affected in about 5 percent of patients, usually males.
In some cases of psoriasis, arthritis causes inflammation of the eyes or the bony sites where ligaments and tendons connect.
Diagnosis
Diagnostic criteria for psoriatic arthritis have not yet been agreed on by the American Rheumatism Association. Because the clinical manifestations of psoriatic arthritis are highly variable, it is difficult to define the disease by symptoms. Currently, a diagnosis of psoriatic arthritis is made in people with psoriasis with symptoms of arthritis and a negative blood test for rheumatoid factor. Conditions that may mimic psoriatic arthritis include gout, Reiter’s syndrome, and rheumatoid arthritis. These conditions should be ruled out with blood and imaging tests. before a diagnosis of psoriatic arthritis is made.
Treatment:
Treatment consists of medications such as cetyl-myristoloeate and non-steroidal anti-inflammatory as well as newer medications that are used to reduce inflammation and pain. Natural therapies include Arthromax , boswellia, omega-3 fatty acids, ginger, devil’s claw, and turmeric. Dietary supplements and lifestyle changes aimed at reducing chronic inflammation are also recommended.
Resources:
Anwar Al Hammadi, Psoriatic Arthritis, eMedicine, August 25, 2006, accessed Jan 15, 2007
Psoriatic Arthritis, The Analyst, accessed Jan 30, 2007.
