What is psoriatic arthritis?
Psoriatic arthritis is a form of inflammatory arthritis. It is a lifelong skin condition that has been diagnosed in over 7 million Americans, according to the National Institutes of Health. Up to 30% of people with psoriasis can develop psoriatic arthritis. Both psoriasis and psoriatic arthritis are chronic autoimmune diseases – meaning, conditions in which certain cells of the body attack other cells and tissues of the body.
Psoriasis is most commonly seen as raised red patches or skin lesions covered with a silvery white buildup of dead skin cells, called a scale. Scales can occur on any part of the body. Psoriasis is not contagious – you cannot get psoriasis from being near someone with this condition or from touching psoriatic scales.
There are 5 different types of psoriatic arthritis. The types differ by the joints involved, ranging from only affecting the hands or spine areas to a severe deforming type called arthritis mutilans.
What are the symptoms of psoriatic arthritis?
The symptoms of psoriatic arthritis may be gradual and subtle in some patients; in others, they may be sudden and dramatic.
The most common symptoms – and you may not have all of these -- of psoriatic arthritis are:
- Discomfort, stiffness, pain, throbbing, swelling, or tenderness in one or more joints
- Reduced range of motion in joints
- Joint stiffness and fatigue in the morning
- Tenderness, pain, or swelling where tendons and ligaments attach to the bone (enthesitis); example: Achilles' tendonitis
- Inflammation of the eye (such as iritis)
- Silver or gray scaly spots on the scalp, elbows, knees, and/or the lower spine
- Inflammation or stiffness in the lower back, wrists, knees or ankles, or swelling in the distal joints (small joints in the fingers and toes closest to the nail), giving these joints a sausage-like appearance
- Pitting (small depressions) of the nails
- Detachment or lifting of fingernails or toenails
Other symptoms (may help a doctor confirm the diagnosis of psoriatic arthritis)
- Positive testing for elevated sedimentation rate (indicates the presence of inflammation)
- Positive testing for elevated C reactive protein (indicates the presence of acute inflammation)
- A negative test for rheumatoid factor and anti-CCP (types of blood tests to help diagnosis certain other forms of arthritis)
- Anemia - a state in which there is a decrease in hemoglobin (protein in the blood that transports oxygen) and red blood cells, which usually causes fatigue, shortness of breath, and a pale appearance
What causes psoriatic arthritis?
The cause of psoriatic arthritis is unknown. Researchers suspect that it develops from a combination of genetic (heredity) and environmental factors. They also think that immune system problems, infection, and physical trauma play a role in determining who will develop the disorder. Psoriasis itself is not an infectious condition.
Recent research has shown that people with psoriatic arthritis have an increased level of tumor necrosis factor (TNF) in their joints and affected skin areas. These increased levels can overwhelm the immune system, making it unable to control the inflammation associated with psoriatic arthritis.