Overview of Psoriatic Arthritis
Psoriatic arthritis is a progressive inflammatory condition of the joints and the places where tendons and ligaments attach to bones (entheses). It happens when the immune system, for unknown reasons, becomes overactive and creates inflammation, leading to pain and swelling. Most people who develop psoriatic arthritis already have psoriasis (a skin disease) when they are diagnosed, but a small fraction have joint pain before the skin rash.
Symptoms appear in different patterns in different people, which can make the disease hard to diagnose. But it is important to see your doctor soon if joint symptoms arise because early treatment is associated with better outcomes and less damage related to the disease.
There is no cure for psoriatic arthritis, but thanks to a better understanding of the disease, treatments can slow its progression, lessen pain, and protect the joints.
Who Gets Psoriatic Arthritis?
Anyone can get psoriatic arthritis, but it is most common in adults, affecting men and women equally. The large majority of people who get it already have psoriasis, and, on average, psoriatic arthritis develops about 7 to 10 years after the onset of skin symptoms. While it is not yet clear who will develop psoriatic arthritis, obesity and having severe psoriasis appear to be associated with a higher risk of arthritis among people with psoriasis. Sometimes stressful events, trauma to the joints or bones, or infections may trigger the disease.
Symptoms of Psoriatic Arthritis
Symptoms of psoriatic arthritis vary greatly from person to person. They may include:
- Scaly, inflamed patches of skin characteristic of psoriasis, often on the scalp, elbows, or knees.
- Joint stiffness, pain, and swelling of one or more joints. The joints of the spine can be affected as well, leading to stiffness in the neck, lower back, and hips. Joint stiffness is often worse in the morning or after resting.
- Fatigue, or feeling tired often or having a lack of energy.
- Tenderness in entheses, areas where tendons or ligaments attach to bones. The back of the heel and sole of the foot are commonly affected spots.
- Painful, sausage-like swelling of a whole finger or toe.
- Nail changes, such as pitting (tiny dents) or crumbling. Nails can also separate from the nail bed.
- Eye inflammation, especially uveitis, inflammation of the middle layer of the eye. This condition can cause eye pain, redness, and blurry vision, and must be treated promptly to avoid vision loss.
- Inflammatory bowel disease, which causes inflammation in the digestive tract, occurs in some people.
Causes of Psoriatic Arthritis
Psoriatic arthritis is an immune-mediated disease, which means that your immune system overacts and causes problems. Scientists do not fully understand why changes in immune activity happen, but they know that certain factors may trigger your immune system, causing the disease. These factors include:
- Genes: Many people who get psoriatic arthritis have a family history of the disease, and researchers have identified some of the genes involved.
- Environment: Factors such as obesity, infection, injury, or stress may trigger the onset of the disease.