Psoriatic arthritis: what is it, symptoms, diagnosis, treatment

If you’re among the estimated 7.5 million Americans dealing with red, itchy skin caused by psoriasis, there’s a chance you may also have joint pain that is brought on by psoriatic arthritis. More than two million Americans suffer from the pain of psoriatic arthritis and many don’t realize they have it and go undiagnosed (Armstrong, 2021; Tiwari, 2021).

Psoriatic arthritis (PsA) is a chronic inflammatory condition that can cause pain and swelling in joints. Flares can start and stop and the pain can be mild or lead to severe disability. Research shows the best way to manage it is to catch it early (Ogdie, 2020). On this front, it helps to sort through what’s causing it, how to best manage it, and to figure out who is at risk. 

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The Greek word ‘psora’ means ‘to itch.’ Combine the itchy, red, scaly skin of psoriasis with the aches of arthritis, and you get a disease that can take a huge toll on daily life. It can affect all ages but has a peak onset in those ages 40 to 50 (Ocampo, 2019).

Psoriatic arthritis can be severe, leading to bone erosion, or milder, causing minor aches in different places around the body. Like psoriasis, the symptoms of psoriatic arthritis vary from person to person. The pain can come and go. It may be just one joint or several in the hand. It may be aching in the tendons of the heel or a lower backache when you wake up. In severe cases, the joints can collapse, causing the fingers to telescope inward (Ocampo, 2019).

It can also make you feel tired. Fatigue, mood changes, and depression are all linked to psoriatic arthritis (Husni, 2017). There is also an increased risk of cardiovascular disease, even osteoporosis (Perez-Chada, 2020). The inflammation of both psoriasis and psoriatic arthritis can affect the entire body, resulting in various health problems, and joint damage can be irreversible. That’s why knowing the causes of PsA, how to treat it and how to spot the signs can make a big difference. 

Like psoriasis, psoriatic arthritis is an immune-mediated disease. An overactive immune system causes flare-ups when the white blood cells called T-cells are triggered. An inflammatory response ramps up leading to pain and potential joint damage. There’s no one exact cause of psoriatic arthritis. Rather, causes appear to be a combination of genetics, personal health risk factors, and environmental factors (Rendon, 2019; Belasco, 2019).

Up to 50% of those with this form of arthritis have a family history of psoriasis or inflammatory arthritis. The genetic risks for psoriasis and psoriatic arthritis are not identical. Some genes that have a link to psoriasis do not have a link to psoriatic arthritis and vice versa. Still, many of the inflammatory pathways are the same (Tiwari, 2021).

Risk factors and triggers

About 30% of those with psoriasis will develop psoriatic arthritis. The following risk factors and triggers can increase the risk that someone with psoriasis develops psoriatic arthritis (Ocampo, 2019; Ogdie, 2015;  Kamiya, 2019): 

• Having severe psoriasis

• Childhood-onset of psoriasis

• Nail psoriasis 

• Obesity

• Alcohol abuse

• Trauma or joint stress 

• Psychological stress

• Infections 

Symptoms of psoriatic arthritis can range from mild to severe and may get worse during skin psoriasis flare-ups. Symptoms may include stiffness in the morning, tender, swollen joints, swollen fingers and toes, painful tendons and muscles, backaches and joint aches that get better with movement, and fingernail or toenail changes (pitting, crumbling, lifting from the nail bed) (Liu, 2014).

There are five types of psoriatic arthritis with different patterns of pain (NIH, 2020; Tiwari, 2021):

• Affects mainly the joints closest to the nails of the fingers and toes. Nail changes are common in this type of psoriatic arthritis (distal interphalangeal predominant)

• Usually involves joints on both sides of the body (symmetric) and can be similar to rheumatoid arthritis (symmetric polyarthritis)

• Involves fewer than five small or large joints on either side of the body (asymmetric); any joint may be affected and may turn red and swell (asymmetric oligoarticular).

• Has spondyloarthritis (inflammation of the spine and joints) pattern; spondylitis can cause pain in the lower back where the spine connects to the hips. Can cause stiffness in the back or neck; joints in arms, legs, feet, and hands may be involved (spondylitis). 

• Involves severe inflammation that damages the joint, particularly in the hands and feet; results in bone loss and can lead to shortening of fingers and toes. Affects about 5% of those with psoriatic arthritis (psoriatic arthritis mutilans).

• About 40% of those with PsA also have dactylitis. This is inflammation of the small joints and enthesitis of the tendons. It typically involves a few fingers or toes and can lead to swelling, leading to the term “sausage digits” (Bagel, 2018).

Inflammation, pain, and the destruction of joints take a toll on the body. Research shows having psoriatic arthritis can impact health in a variety of ways. Having psoriatic arthritis puts one at an increased risk for conditions such as (Perez-Chada, 2020): 

• Cardiovascular disease

• Metabolic syndrome (Atzeni, 2021)

• Obesity

• Diabetes

• Dyslipidemia (abnormal cholesterol)

• Inflammatory bowel disease

Talking about the emotional and social impacts of psoriatic arthritis is also part of many treatment plans. That’s because PsA can affect the quality of life. According to one study, those with psoriatic arthritis often experience (Husni, 2017):

• Sleep disorders

• Fatigue

• Low-level stress

• Depression

• Mood and behavior changes

• Poor body image

• Reduced work productivity

Researchers say a team of healthcare providers should manage psoriatic arthritis with both physical and psychological assessments (Husni, 2017).

About 15% of people with psoriatic arthritis go undiagnosed. People can confuse the symptoms with other types of arthritis and conditions or ignore them altogether. Most with psoriatic arthritis have had skin symptoms, which can make diagnosis easier. However, about 17% of people get PsA before skin changes, making the diagnosis harder (Tiwari, 2021).

Even a six-month delay in diagnosing psoriatic arthritis can be enough time to allow noticeable joint damage to occur (Ogdie, 2020). 

A dermatologist often treats psoriasis, but when it involves arthritis, a rheumatologist who specializes in joint conditions can help identify the causes and determine what type of arthritis is causing pain. Diagnosis typically involves (Tiwari, 2021):

• Examining skin, scalp, and nails, as well as affected joints and pain patterns

• X-ray to check for joint damage

• Ultrasound, MRI, or CT scan for more detail

• Blood tests  (may be done to rule out other types of arthritis)

• Skin biopsy (only if needed to confirm psoriasis)

Screening Tools

Among those with psoriasis, healthcare providers use screening questionnaires to identify who is at greatest risk for psoriatic arthritis. You may have had to answer questions from the Psoriasis Epidemiology Screening Tool (PEST). Among the questions: ‘Have you had pain in your heel?’ and ‘Have you had a finger or toe that was completely swollen and painful for no apparent reason?’ PEST is one of several screening questionnaires designed to help spot signs of PsA early. (Setoyama, 2021; Iragorri, 2019).

Treating PsA is based on symptoms, joint damage, other health problems, and each person’s goals for treatment. To avoid unnecessary side effects, there’s an effort to use the lowest amount of medication required to treat pain and stop joint destruction.

In 2018, the American College of Rheumatology and the National Psoriasis Foundation released new psoriatic arthritis treatment guidelines (Singh, 2018). In mild cases, some choose to treat only the symptoms. In more severe cases, stopping the disease from getting worse (“disease progression”)  is typically the goal. 

Treating symptoms involves non-steroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, or glucocorticoid injections to alleviate pain.

To stop disease progression, medical experts recommend systemic medications. Traditional treatments, including methotrexate, sulfasalazine, cyclosporine, leflunomide, and apremilast, are effective. Newer biological drugs, which come from living cells, include tumor necrosis factor (TNF) inhibitors and various other drugs like ustekinumab (Stelara), secukinumab (Cosentyx), and  Abatacept (Orencia), which block specific targets in the immune/inflammatory response. 

Many of the newer biological drugs can effectively clear skin of psoriasis and curb joint destruction while tamping down inflammation. Some argue this can also reduce the risk of other inflammatory diseases linked to psoriatic arthritis, such as cardiovascular disease and metabolic syndrome (Atzeni, 2021).

All disease-modifying medications, including newer biologics, have side effects. Treatment decisions are highly personalized, and it’s important to work with a healthcare provider to discuss risk factors and monitor treatment (Liu, 2014).

In addition to medicines, there are complementary therapies and lifestyle approaches healthcare providers often suggest. These include physical or occupational therapy, quitting smoking, weight loss, massage therapy, and exercising (Singh, 2018).

Early diagnosis of psoriatic arthritis can help prevent joint damage. If you have psoriasis, your healthcare provider can help you watch for early signs of PsA. If you don’t have skin rashes but notice aching joints or heels, swollen fingers or toes, or pitted, lifting nails, it’s important to see a healthcare provider to either rule out or confirm a diagnosis of PsA and/or psoriasis. Treating both conditions also helps tamp down inflammation in the body (Tiwari, 2021). 

If you feel PsA is affecting your quality of life, the National Psoriasis Foundation offers additional advice on reaching out for support. 

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Current version

October 07, 2021

Written by

Kristin DeJohn

Fact checked by

Felix Gussone, MD

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About the medical reviewer

Felix Gussone, MD, Ro

Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.