An estimated 30% of people in the U.S. who have psoriasis will develop psoriasis arthritis in their lifetime. Maybe you are confused what it is. It is psoriasis or arthritis? Or is it both? This article will explain what psoriatic arthritis is, the types and diagnosis of psoriasis arthritis.
What is psoriatic arthritis?
Psoriatic arthritis is a long-term autoimmune disease characterized by a form of inflammation of the skin (psoriasis) and joints (inflammatory arthritis). The classic feature of psoriatic arthritis is swelling of entire fingers and toes with a sausage-like appearance. This often happens in association with changes to the nails such as small depressions in the nail, thickening of the nails, and detachment of the nail from the nailbed.Signs and symptoms of skin changes include patchy, itchy plaques, scaly, raised, red areas of skin inflammation with scaling. About 40 percent of psoriatic arthritis patients have a family history of psoriasis or arthritis. Psoriatic arthritis may be misdiagnosed as gout or rheumatoid arthritis. Psoriatic arthritis, unlike rheumatoid arthritis, may only need to be treated when symptoms arise.
Diagnosis of psoriatic arthritis
Psoriatic arthritis cannot be diagnosed with a simple blood test. However, symptoms of psoriatic arthritis are similar to those of RA, so a blood test will probably be ordered to rule out RA. X-rays are not always useful in diagnosing early-stage psoriatic arthritis. As the disease progresses, imaging tests can be used to see changes in the joints that are characteristic of this type of arthritis. CT scans and ultrasounds can help determine progression. People with psoriatic arthritis can be misdiagnosed with gout, a form of arthritis caused by too much uric acid in the body. Gout usually affects the big toes. Fluid can be taken from an affected joint to determine if it contains uric acid crystals. It is also possible to have gout, psoriasis, and psoriatic arthritis at the same time.
Types of psoriasis arthritis
Oligoarticular: It affects around 70% of patients and is generally mild. It does not occur in the same joints on both sides of the body and usually only involves fewer than 3 joints.
Polyarticular: It accounts for around 25% of cases, and affects five or more joints on both sides of the body simultaneously. It is most similar to rheumatoid arthritis and is disabling in around 50% of all cases.
Arthritis mutilans (M07.1): Affects less than 5% of patients and is a severe, deforming and destructive arthritis. This condition can progress over months or years causing severe joint damage. Arthritis mutilans has also been called chronic absorptive arthritis, and may be seen in rheumatoid arthritis as well.
Spondyloarthritis (M07.2): It is characterized by stiffness of the neck or the sacroiliac joint of the spine, but can also affect the hands and feet, in a similar fashion to symmetric arthritis.
Distal interphalangeal predominant (M07.0): This type of psoriatic arthritis is found in about 5% of patients, and is characterized by inflammation and stiffness in the joints nearest to the ends of the fingers and toes. Nail changes are often marked.