Psoriatic arthritis (PsA) is a type of inflammatory arthritis related to psoriasis. Approximately one-third of people with psoriasis are affected by psoriatic arthritis. PsA generally affects the joints and the areas where ligaments and tendons connect to bones.

What Causes Psoriatic Arthritis?

Psoriatic arthritis and psoriasis are autoimmune conditions — conditions that occur when the immune system mistakenly attacks healthy tissues, such as 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. Psoriatic arthritis is caused by several factors. Researchers have identified dozens of genetic variants that may make a person more likely to develop psoriasis and PsA.

Most scientists believe that genetics and environmental factors both contribute to psoriatic arthritis, but they’re still working to understand exactly why a person develops the condition. Researchers believe that environmental factors — a physical injury, a virus, or an infection like strep throat — may trigger the development of psoriatic arthritis for some people who are genetically predisposed. These are all situations that set off an immune response.

Risk Factors for Psoriatic Arthritis

Having psoriasis is the primary risk factor for developing psoriatic arthritis. Psoriatic arthritis affects about 30 percent of people with psoriasis, according to the National Psoriasis Foundation. Psoriatic arthritis usually develops in people between the ages of 30 and 50. However, not everyone with psoriatic arthritis receives a psoriasis diagnosis first. Between 10 percent and 15 percent of people with psoriatic arthritis experience joint symptoms without ever having skin symptoms.

​Having a family history of psoriasis or psoriatic arthritis is another risk factor. Whereas being female is sometimes a risk factor for other autoimmune conditions, psoriatic arthritis affects all genders equally.

How Is Psoriatic Arthritis Diagnosed?

Your dermatologist or primary care physician may refer you to a rheumatologist if you have symptoms of psoriatic arthritis. 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 psoriatic arthritis are 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 your fingers and toes. They may recommend various tests to look for signs of psoriatic arthritis and to rule out other possible causes.

Tests for Psoriatic Arthritis

There is no single test for diagnosing psoriatic arthritis. A rheumatologist will need to look at several factors before making a diagnosis. A final diagnosis will be based on your symptoms and the results of various tests.

Imaging Tests

A rheumatologist may order an imaging test to look for signs of psoriatic arthritis. X-rays can detect severe bone changes that can be caused by psoriatic arthritis, and they are most effective at diagnosing later-stage PsA. They’re not as good at detecting early-stage psoriatic arthritis.

Ultrasound and magnetic resonance imaging (MRI) may also be used to look for inflammation of joints and tendons. These tests can detect early changes in psoriatic arthritis, such as inflammation in the tendons or the joints of the back and pelvis. They can also help rule out other possible diagnoses.

Blood Tests

No specific blood test can confirm a psoriatic arthritis 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:

• Rheumatoid factor (RF) is an antibody found in people with rheumatoid arthritis. A positive RF test result can help rule out psoriatic arthritis.
• C-reactive protein (CRP) tests can detect inflammation.
• Erythrocyte sedimentation rate (ESR) is another test used to detect inflammation.
• Human leukocyte antigen (HLA) B27 is a gene associated with several autoimmune diseases. A positive test result is frequently associated with ankylosing spondylitis, but it can also be detected in people diagnosed with PsA and spine or sacroiliac joint involvement.

Biopsies and Other Tests

Biopsies are sometimes used to help confirm a diagnosis of psoriatic arthritis or rule out other conditions. Your doctor may perform the following types of procedures:

• Arthrocentesis, or joint fluid analysis, is performed by removing fluid from an affected joint with a needle. It can help rule out gout.
• A skin biopsy, which involves removing a small skin sample for testing, may be performed to confirm psoriasis or another skin condition.

What Are the Symptoms of Psoriatic Arthritis?

Psoriatic arthritis causes joint pain, swelling, and stiffness. Psoriatic arthritis symptoms may be mild or have a severe impact on quality of life. Below are some psoriatic arthritis symptoms to look out for.

Dactylitis

Also referred to as “sausage digits,” dactylitis is a painful, red or purple swelling in the fingers and toes. It’s often the first symptom of psoriatic arthritis.

Enthesitis

People with psoriatic arthritis may 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, knees, and ribs.

Nail Changes

White spots, flaking, pitting (shallow or deep dents on your nails), or lifting of the nail bed may also be symptoms of psoriatic arthritis. Up to 90 percent of people with psoriatic arthritis experience nail changes, much more frequently than people who only have skin psoriasis.

Skin Psoriasis

Itchy, scaly, red, purple, or silvery lesions appear prior to the onset of psoriatic arthritis in approximately 75 percent of people with psoriatic arthritis. Psoriasis plaques can appear on the skin 10 to 20 years before joint symptoms.

Other Psoriatic Arthritis Symptoms

Not all psoriatic arthritis symptoms affect the skin and joints. Other possible symptoms include uveitis (an inflammatory eye condition more often associated with a positive HLA-B27 test result), inflammatory intestinal diseases, and general symptoms such as fatigue.

What Are the Types of Psoriatic Arthritis?

Psoriatic arthritis can be broken into five categories defined by the impacted joints. It’s possible to have more than one type of psoriatic arthritis.

Asymmetric Oligoarthritis

An estimated 35 percent of people with psoriatic arthritis have this type. Asymmetric oligoarthritis typically involves five or fewer joints. It’s known as asymmetric arthritis because it typically doesn’t affect both sides of the body in the same place. For example, it might appear in only one knee or one elbow.

Symmetric Polyarthritis

Symmetric polyarthritis is one of the most common types of psoriatic arthritis — half of all people with PsA are estimated to have this type. Symmetric polyarthritis affects five or more corresponding joints on both sides of the body. This type of psoriatic arthritis is similar to rheumatoid arthritis, but it can be differentiated by a few factors, including a negative RF blood test.

Spondylitis

Psoriatic arthritis that affects the lower back and spine is a type of spondylitis (also called spondyloarthritis). About 5 percent of people with psoriatic arthritis have spondylitis and will have a positive HLA-B27 test.

Distal Arthritis

Distal arthritis causes inflammation and stiffness in the distal interphalangeal joints, those closest to the tips of fingers and toes. According to Cleveland Clinic, this type affects about 10 percent of people with psoriatic arthritis, usually men. Nail changes are also common with distal arthritis.

Arthritis Mutilans

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.

How Is Psoriatic Arthritis Treated?

There is no cure for psoriatic arthritis, but different treatment options can control disease activity, reduce symptoms, and protect joint mobility. Treatment generally aims to manage pain, reduce inflammation, and slow disease progression. Below are the main classes of medications used to treat psoriatic arthritis.

Traditional Disease-Modifying Antirheumatic Drugs

Traditional disease-modifying antirheumatic drugs, or DMARDs, help reduce joint damage, slow disease progression, and relieve symptoms by suppressing the immune system. These include:

• Cyclosporine
• Leflunomide (Arava)
• Methotrexate
• Sulfasalazine

Biologics

Biologics, sometimes called biologic DMARDs, target specific proteins that contribute to inflammation in psoriatic arthritis. They may be prescribed when traditional DMARDs are ineffective. Biologic DMARDs block certain proteins in the body that maintain inflammation. The following biologics are FDA-approved for treating psoriatic arthritis:

Tumor Necrosis Factor-Alpha Inhibitors

• Adalimumab (Humira)
• Certolizumab pegol (Cimzia)
• Etanercept (Enbrel)
• Golimumab (Simponi, Simponi Aria)
• Infliximab (Remicade)

Interleukin 12 and 23 (IL-12/23) Inhibitors

• Ustekinumab (Stelara)

Interleukin 17 (IL-17) Inhibitors

• Bimekizumab-bkzx (Bimzelx)
• Brodalumab (Siliq)
• Ixekizumab (Taltz)
• Secukinumab (Cosentyx)

Interleukin 23 (IL-23) Inhibitors

• Guselkumab (Tremfya)
• Risankizumab-rzaa (Skyrizi)
• Tildrakizumab-asmn (Ilumya)

Interleukin 36 (IL-36) Inhibitors

• Spesolimab-sbzo (Spevigo)

T-Cell Inhibitors

• Abatacept (Orencia)

Biosimilars are available for certain biologic medications. Biosimilars are highly similar to previously approved biologic medications, but they are often more affordable. They are used to treat psoriatic arthritis in the same way as the original biologic. Talk to your dermatologist if you’re interested in learning more about them.

Janus Kinase Inhibitors

Janus kinase (JAK) inhibitors block enzymes that contribute to the inflammatory process in autoimmune conditions. These are typically used when other treatments haven’t been effective. FDA-approved JAK inhibitors for psoriatic arthritis include:

• Tofacitinib (Xeljanz)
• Upadacitinib (Rinvoq)

Other Medications

Other treatments used to manage psoriatic arthritis include:

• Apremilast (Otezla) — This phosphodiesterase 4 (PDE4) inhibitor helps reduce inflammation.
• Corticosteroids — These can be injected directly into inflamed joints or taken orally to manage flare-ups. Long-term use is generally avoided because of the risk for side effects.

Pain Management

For mild cases of psoriatic arthritis, nonsteroidal anti-inflammatory drugs (NSAIDs) may be used to manage symptoms like pain and swelling. NSAIDs work best for people who have psoriatic arthritis with spondylitis. Common NSAIDs include ibuprofen (Advil, Motrin) and naproxen (Aleve).

Other Treatments for Psoriatic Arthritis

Physical therapy can help manage psoriatic arthritis. For severe joint damage, surgery may be appropriate. Lifestyle changes like eating a healthy diet and quitting smoking can also help.

Conditions Related to Psoriatic Arthritis

When someone has more than one health condition at the same time, the conditions are known as comorbidities. Cardiovascular diseases are the most common condition present in combination with psoriatic arthritis. Diabetes and metabolic dysfunction-associated steatotic liver disease (previously known as nonalcoholic fatty liver disease) are other conditions that many people have in addition to psoriatic arthritis.

Talk With Others Who Understand

MyPsoriasisTeam is the social network for people with psoriasis and their loved ones. On MyPsoriasisTeam, more than 131,000 members come together to ask questions, give advice, and share their stories with others who understand life with psoriasis.

Do you have psoriatic arthritis? What symptoms did you first notice? Share your experience in the comments below, or start a conversation on your Activities page.