Psoriatic arthritis (PsA) is an inflammatory condition of the joints which can cause pain and swelling in affected joints and areas with tendons and ligaments, which may lead to stiffness and reduced movement.
Psoriatic arthritis (PsA) most commonly affects the joints in the hands and feet, but can also affect larger joints, including the knees, elbows, hips and the spine. Symptoms can develop slowly, and many people may not realise they are developing PsA.
Most people who have psoriatic arthritis find it occurs after developing skin psoriasis, but some do develop the arthritis before they notice any psoriasis on their skin.
Although having psoriasis means you are more at risk of developing psoriatic arthritis, it is not always linked to how severe your psoriasis is. People with mild or moderate psoriasis can also develop psoriatic arthritis, which is why it is important to be aware of the symptoms.
As with psoriasis, a family history of the condition does not necessarily mean a person will develop psoriatic arthritis.
Have a look at our information leaflet on psoriatic arthritis for more information.
In psoriatic arthritis, the joints affected may become tender, swollen and stiff. These symptoms tend to be worse first thing in the morning and with rest, and ease with exercise. Inflammation of tendons without obvious inflammation of the joints can also occur in psoriatic arthritis, which makes it easy to misdiagnose as tendonitis or tennis elbow, for example. Psoriatic arthritis commonly affects the small joints of the hands and feet, and so a swollen sausage-like finger or toe is another common sign.
It is difficult to say how many people with psoriasis develop psoriatic arthritis (PsA), but it is thought that around one quarter of people with psoriasis will go on to develop psoriatic arthritis. Men and women are equally likely to develop psoriatic arthritis and, although it can occur at any age, it is most common in the first decade of being diagnosed with psoriasis.
In line with this, most people have psoriasis on their skin before they notice symptoms of psoriatic arthritis. However, in some cases the skin and joint conditions occur at the same time, and sometimes psoriatic arthritis is present before the skin condition psoriasis appears. It is worth noting that people with psoriasis can also develop other forms of arthritis such as rheumatoid arthritis and osteoarthritis. Having psoriasis does not necessarily mean that aches and pains or other joint symptoms are psoriatic arthritis.
Nail psoriasis is present in a large number of people with psoriatic arthritis (estimated as between 50 and 80%). Nail psoriasis can and does occur in people who do not have psoriatic arthritis, but, because of the large amount of people who have both conditions, it can be an important indicator of possible psoriatic arthritis.
People with psoriasis affecting the nails, scalp, or palmoplantar psoriasis may have a slightly higher chance of developing psoriatic arthritis, usually a few years after the psoriasis first appears. For this reason, it is important to be aware of any possible new joint symptoms, such as pain, swelling, or stiffness, and to mention these to your healthcare professional if they occur.
If psoriatic arthritis is suspected, you should seek a referral to a Rheumatologist as soon as possible.
There is no conclusive test for psoriatic arthritis, and it can therefore be a difficult condition to diagnose.
Psoriatic arthritis is an inflammatory joint disease closely associated with psoriasis, which affects the joints and tendons. ‘Inflammatory arthritis’ means that there is inflammation present in the affected joints, rather than just wear and tear. It can be difficult to diagnose, as symptoms can be similar to other types of arthritis, and a patient does not necessarily have to have psoriasis to develop it. It is also possible for people with psoriasis to develop a different type of arthritis (such as rheumatoid arthritis or osteoarthritis); the fact that they have psoriasis does not alone mean their arthritis is psoriatic.
At present there are no definitive guidelines for diagnosing psoriatic arthritis and there is no single test that can confirm it. If you think you may have psoriatic arthritis, it is important that you discuss this with your GP (or Dermatologist if you are seeing one for your skin psoriasis). They can then refer you to a Rheumatologist (a specialist in joint conditions) for an assessment.
A diagnosis will then be made based on your symptoms, your medical history, and by ruling out other conditions. Several blood tests may be carried out to confirm a diagnosis including blood tests to check for signs of inflammation in your body as well as the presence of certain antibodies found in other types of arthritis.
A doctor may also use x-rays, ultrasounds, or other scans, such as an MRI to look at your joints. These scans can often show inflammation or areas of new bone growth with poorly defined edges in people with psoriatic arthritis.
For more information on diagnosing psoriatic arthritis, have a look at our information sheet.