What is Psoriatic Arthritis?
Psoriatic arthritis is a form of arthritis linked to psoriasis. It causes joint swelling and pain in multiple joints and can sometimes result in joint deformation.
Not everyone who has psoriasis will get psoriatic arthritis. Most of the time (80%), psoriasis comes first. Psoriasis is a skin disease that causes scaly, red/white plaques. Both diseases are caused by your immune system being inappropriately activated.
How common is the disease?
Psoriatic arthritis affects 1-2 people for every 1000 people. Each year, there will be around 6 new cases diagnosed. Men and women are affected equally.
It is still not clear how many people who have psoriasis will get psoriatic arthritis. Estimates range from 4-30%, depending on what part of the world you live in. Most people with new onset joint pain do not have psoriatic arthritis (only 13%).
What causes psoriatic arthritis?
The exact cause is not yet known, although doctors and researchers think that it is a combination of genetics, environment, and individual immune system. Current research has found that psoriatic arthritis is hereditary and associated with certain genes associated with autoimmune diseases.
What symptoms will I experience with psoriatic arthritis?
Psoriatic arthritis causes pain and stiffness in affected joints. Joint pain can be prolonged in the morning (over 30 minutes). It might feel worse when staying immobile and is alleviated with physical activity. Some people do not experience severe joint pain but will have joint deformity.
Your joints might not be affected the same way on both halves of your body. Some of the most common affected joint areas are the finger joints nearest the fingertip as well as the spine.
How do I know if I have psoriatic arthritis?
Your doctor will consider your medical history and examine your affected joints. They will also order blood tests to check for markers of inflammation and markers that might suggest other diseases. Your doctor may also choose to biopsy fluid from your joint capsule or obtain X-rays.
When examining your joints, your doctor will look for certain key features that are commonly found in psoriatic arthritis. These include tendon and ligament inflammation (called enthesitis), inflammation of the fluid-filled sheath of a joint (called the synovium), and sausage-like swelling of an entire digit (called dactylitis).
It is possible that your joint pain is caused by other joint disease, which include osteoarthritis, rheumatoid arthritis, gout, reactive arthritis, or arthritis related to inflammatory bowel disease. Your doctor will exclude these conditions before making a diagnosis.
Some doctors might use screening questionnaires to identify if you have psoriatic arthritis. In cases where they are not certain, you might be referred to a rheumatologist for further investigation.