Psoriatic arthritis (PsA) is a type of inflammatory arthritis related to psoriasis. Approximately one-third of people with psoriasis are affected by PsA. Psoriatic arthritis generally affects the joints and areas where ligaments and tendons connect to bones.
Psoriatic arthritis and psoriasis are autoimmune diseases — conditions that occur when the immune system mistakenly attacks healthy tissues like your skin and joints. Inflammation from the body’s overreacting immune response leads to symptoms of psoriasis and PsA. Psoriatic arthritis is distinct from osteoarthritis, which is caused by the normal wear and tear of aging, rather than inflammation.
Most scientists believe that genetics and environmental factors both contribute to PsA, but they are still working to understand exactly why a person develops PsA. Researchers theorize that environmental factors — a physical injury, a virus, or an infection like strep throat — may trigger the development of PsA in some people. These are all situations that set off an immune response.
Having psoriasis is the primary risk factor for developing psoriatic arthritis. Psoriatic arthritis affects about 30 percent of people with psoriasis. PsA usually develops between the ages of 30 and 50. However, not everyone with PsA receives a psoriasis diagnosis first. Between 10 percent and 15 percent of those with PsA experience signs of arthritis without ever having skin symptoms.
Family history of psoriasis or psoriatic arthritis is another risk factor — 40 percent of people with PsA have a family history of psoriatic disease. Unlike many other autoimmune diseases, being a woman is not a risk factor. Men and women are at equal risk of developing PsA.
Your dermatologist or primary care physician may refer you to a rheumatologist if you have symptoms of PsA. A rheumatologist is trained to diagnose and treat joint and tendon symptoms, while a dermatologist is focused on the skin symptoms of psoriasis and other skin conditions. Early diagnosis and treatment of PsA is associated with better outcomes.
A rheumatologist will conduct a physical exam and take a medical history. Your doctor will check to see if your joints are swollen or tender. They will likely pay special attention to the fingers and toes. They may then recommend various tests to look for signs of PsA and to rule out other possible causes.
There isn’t one simple test for diagnosing psoriatic arthritis. A rheumatologist will need to evaluate several factors before giving a diagnosis. A final diagnosis will be based on your symptoms and the results of various tests.
A rheumatologist may order an imaging test to look for signs of psoriatic arthritis.
There is no specific blood test that can confirm a PsA diagnosis. Instead, blood tests are used to detect inflammation and rule out other types of arthritis. Below are some types of blood tests your doctor may order:
Biopsies are sometimes used to help confirm a diagnosis of PsA or rule out other conditions. Your doctor may perform the following types of biopsies:
Learn more about psoriatic arthritis diagnosis and tests.
Psoriatic arthritis is characterized by joint pain, swelling, and stiffness. PsA symptoms may be mild or have a severe impact on quality of life.
It’s common for people with PsA to have enthesitis, a condition characterized by pain or tenderness where ligaments and tendons attach to bone. Enthesitis most frequently occurs in the heels and bottoms of the feet, though it can also affect the elbows.
White spots, flaking, pitting (shallow or deep dents on your nails), or lifting of the nail bed may also be symptoms of psoriatic arthritis. You might notice changes to your nails without experiencing joint pain. Up to 90 percent of people with PsA experience nail changes.
Itchy, scaly, red, purple, or silvery lesions appear prior to the onset of psoriatic arthritis in approximately 75 percent of people with PsA. Skin disease can appear 10 to 20 years before developing joint symptoms.
Not all PsA symptoms affect the skin and joints. Other possible symptoms include:
Read more about symptoms of psoriatic arthritis.
There are five primary types of psoriatic arthritis, each defined by the impacted joints. It’s possible to have more than one type of PsA.
Asymmetric oligoarthritis occurs in 70 percent to 80 percent of people with PsA. The mildest form of PsA, it typically involves one to four joints on just one side of the body.
Symmetric polyarthritis affects 5 percent to 20 percent of people with psoriatic arthritis. Symmetric polyarthritis may start with minimal joint involvement on one side of the body and progress to several joints on both sides of the body.
Psoriatic arthritis that affects the lower back and spine is a type of spondylitis (also called spondyloarthritis). Between 5 percent and 20 percent of people with PsA have spondylitis. You can learn more about spondylitis at MySpondylitisTeam.
Distal arthritis causes inflammation and stiffness in the distal interphalangeal joints, those closest to the tips of fingers and toes. This type affects about 10 percent of people with PsA. Nail changes are also common with distal arthritis.
Arthritis mutilans is the rarest and most severe type of psoriatic arthritis. This form of PsA attacks joints in the hands and feet, causing deformities and impaired movement.
While there is currently no cure for psoriatic arthritis, there are treatment options that can control disease activity and reduce painful symptoms. Goals for PsA treatment include reducing pain and inflammation and protecting joint mobility.
Disease-modifying antirheumatic drugs (DMARDs) are the main category of drugs that slow joint damage. Conventional DMARDs and newer targeted DMARDs are taken as pills. Under the DMARD umbrella are biologic drugs administered via injection or infusion. Biologic drugs are usually only prescribed if other medications haven’t been effective.
Nonsteroidal anti-inflammatory drugs (NSAIDs), like Advil or Motrin (ibuprofen), can reduce swelling and pain. They are typically prescribed for mild cases of psoriatic arthritis without joint damage.
Corticosteroids can also be used to treat PsA symptoms. Corticosteroids can be given as an injection to treat inflammation in a specific joint. Oral corticosteroids can be used to treat a PsA flare, though they may exacerbate psoriasis. Long-term use of steroids is generally discouraged due to side effects.
Physical therapy, as well as lifestyle changes like eating a healthy diet and quitting smoking, can help manage psoriatic arthritis. In cases of severe joint damage, surgery may be appropriate.
Research into treatments for PsA is ongoing. Clinical trials are underway to investigate new treatments.
Learn more about treatments for psoriatic arthritis.
When someone has more than one health condition at the same time, the conditions are known as comorbidities. Cardiovascular disease is the most common comorbidity for people with PsA. Diabetes, obesity, and nonalcoholic fatty liver disease are other conditions that many people have in addition to PsA.