Psoriatic arthritis

Psoriatic arthritis is driven by the immune system mistakenly causing inflammation in and around the joints, the spine and the entheses, the points where tendons and ligaments attach to bone. It belongs to the spondyloarthritis family, alongside axial spondyloarthritis and reactive arthritis, and shares features with them.

There is no single cause. It reflects a combination of genetic susceptibility, often with a family history of psoriasis or related conditions, and as yet unclear triggers. It is most common in people who already have psoriasis, though the joint problems can precede the rash. Smoking, obesity and physical stress on tendons are recognised associations, and it affects men and women fairly equally, usually appearing between the ages of 30 and 50.

Psoriatic arthritis can show itself in several ways, and the pattern varies from person to person. Features may include:

• Painful, swollen joints, which can affect the fingers, toes, knees and other joints
• Swelling of a whole finger or toe, giving a sausage-like appearance
• Pain where tendons attach to bone, such as the heel or the back of the elbow
• Back or buttock pain when the spine is involved
• Nail changes, such as pitting or lifting, often alongside psoriasis of the skin

Diagnosis draws together your symptoms, any history of psoriasis (including in the family), an examination and appropriate tests. There is no single blood test that confirms it, so the overall picture matters.

Ultrasound is especially helpful in psoriatic arthritis because it can detect inflammation in tendons and at their attachments, as well as in the joints, sometimes before it is visible or easily felt. As Dr Borukhson performs point-of-care ultrasound during the consultation, this can often be assessed in the same visit. You can read more on the ultrasound clinic page.

The aim is to control the inflammation, relieve symptoms and protect the joints and tendons, while also considering the skin. Treatment is individual and is discussed fully with you, and as with other types of inflammatory arthritis, starting effective treatment early gives the best long-term result.

A range of medications can calm the overactive immune response. Disease-modifying anti-rheumatic drugs (DMARDs) such as methotrexate, sulfasalazine or leflunomide are often used first, and where the joints, spine or tendons remain active, biologic or targeted therapies (for example anti-TNF or anti-IL-17 medicines) are a further option, chosen with the skin in mind because some also help psoriasis. These medicines are discussed fully with you and used under specialist supervision: methotrexate needs regular blood tests, biologic medicines need screening beforehand because they can raise the risk of infection, and treatment around pregnancy is planned carefully where relevant. The plan is reviewed over time. Where a particular joint or tendon remains troublesome, an ultrasound-guided injection may help. Any treatment is agreed with you.

Alongside your treatment, a few measures genuinely help. Keeping active matters: gentle, regular movement maintains joint mobility and eases stiffness, and combining this with stretching protects the tendons and entheses that this condition tends to involve.

• Reach and keep a healthy weight, which reduces load on the joints and can improve how well some medicines work
• Stop smoking, as it worsens both psoriasis and the arthritis and blunts treatment response
• Pace activity through flares, balancing rest with movement rather than stopping altogether
• Care for your skin and nails, and report flares, as skin and joint disease often track together

Like other types of inflammatory arthritis, psoriatic arthritis carries a somewhat higher risk to the heart over the years. Keeping the inflammation well controlled is one of the best ways to lower that risk, and our guide to inflammation and your heart explains the simple checks worth asking about.

The outlook is generally good. With early, well-monitored treatment most people keep the condition well controlled, though it tends to be long-term and is managed over time rather than cured.

Contact your rheumatology team promptly if a joint becomes newly swollen, hot or much more painful, if a whole finger or toe swells, or if new back, buttock or heel pain develops, as these may signal active disease that needs the treatment plan reviewed.

Some situations are more urgent. Seek same-day medical advice if you develop a fever, feel unwell or have a hot, acutely painful joint while on a DMARD or biologic, since these medicines raise the risk of infection, which occasionally needs to be distinguished from a flare. A red, painful eye with light sensitivity should also be assessed quickly, as inflammation can affect the eye in this group of conditions.

For anything that feels severe, sudden or systemically unwell, do not wait for a routine appointment.

Treated early, psoriatic arthritis can usually be well controlled and joint damage limited. NICE notes that the signs and symptoms of spondyloarthritis, the family of conditions to which psoriatic arthritis belongs, are not always recognised in non-specialist settings, and that this can lead to substantial delays in diagnosis and treatment, with consequent disease progression and disability. If you have psoriasis and develop joint pain, swelling, or heel or tendon pain, a specialist review is worthwhile, even if the symptoms seem minor.

How soon should I be seen if I have psoriasis and joint pain?

Promptly. NICE advises referral to a rheumatologist as soon as psoriatic arthritis is suspected, and recommends that people with psoriasis are assessed for it every year, especially within the first ten years of the skin condition. Across this group of conditions, delays in diagnosis and treatment can lead to disease progression and disability, so early treatment gives the best chance of limiting joint damage.

Can I have psoriatic arthritis if my psoriasis is mild or has not appeared yet?

Yes. The arthritis sometimes develops long after the skin is first affected, and occasionally before any rash appears at all. A family history of psoriasis and nail changes such as pitting or lifting are also relevant, which is why the assessment considers the whole picture rather than the skin alone.

What will be examined at the first appointment?

Your history is reviewed, including any personal or family history of psoriasis, and the examination covers the joints, the spine and the places where tendons attach to bone, such as the heel. Dr Borukhson performs point-of-care ultrasound during the consultation, which is particularly useful in psoriatic arthritis because it can detect inflammation in tendons and at their attachments before it is easy to see or feel.

Will treatment for my joints help my skin too?

It can. Some biologic medicines used for psoriatic arthritis also help psoriasis, so the choice of treatment takes the skin into account as well as the joints and tendons. The plan is reviewed over time and any change is agreed with you.

What monitoring is involved with treatment?

That depends on the medicines involved. Methotrexate needs regular blood tests, and biologic medicines need screening before they start because they can raise the risk of infection. Where pregnancy is relevant, treatment is planned carefully around it, and follow-up appointments keep the plan under review.