Psoriatic arthritis

Psoriatic arthritis is a type of arthritis that sometimes develops in people who have the skin condition psoriasis. It affects the joints, and they can become swollen, stiff and painful.

It's estimated that around 1 in 4 patients with psoriasis have psoriatic arthritis.

Most people notice problems with their skin first, before any joint symptoms appear. In a small number of cases, the skin problems start at the same time as the joint problems, or after them.

Psoriatic arthritis can be caused by the immune system wrongly attacking healthy tissue. It isn't clear why some people with psoriasis go on to develop it and others don't.

Psoriatic arthritis can affect any joint in the body. It causes pain, swelling and stiffness in the joints, and it often shows up in particular areas, including the:

• hands
• feet
• knees
• elbows
• neck and spine

Psoriatic arthritis can also affect the place where tendons and ligaments connect to the bone. This is called the entheses, or enthesitis when it becomes inflamed.

Sometimes a whole finger or toe gets inflamed and looks sausage-like. This is called dactylitis.

Symptoms usually come on slowly, so many people don't realise psoriatic arthritis is developing. In rare cases, symptoms appear suddenly without warning.

How severe it is varies from person to person. Some people have severe problems affecting many joints. Others notice only mild symptoms in 1 or 2 joints.

Your symptoms may get better and then worse again at different times. These periods are called flare-ups or relapses. Some people reach a point where they have no symptoms at all (known as remission).

Relapses can be hard to predict, but they can be managed with medicine.

Go to a doctor if you have any of these:

• constant pain in your joints
• swelling in your joints
• stiffness in your joints

You should do this even if you haven't been diagnosed with psoriasis.

If you have been diagnosed with psoriatic arthritis, you should have check-ups at least once a year. Tell your doctor if you notice any problems with your joints.

If your doctor thinks you may have psoriatic arthritis, they should refer you to a rheumatologist for an assessment. A rheumatologist is a specialist in joint conditions.

If you have psoriasis and problems with your joints, a rheumatologist should be able to diagnose psoriatic arthritis. Other types of arthritis, like rheumatoid arthritis and osteoarthritis, would need to be ruled out first.

You may be given some tests to help confirm the diagnosis, including:

• blood tests to check for signs of inflammation and other types of arthritis
• X-rays of your joints
• scans of your joints

Treatment for psoriatic arthritis has three main aims:

• to help your symptoms
• to slow the progression of the condition
• to improve your quality of life

Your doctor may prescribe medicine to treat psoriatic arthritis. For example:

• non-steroidal anti-inflammatory drugs (NSAIDs)
• steroid medicines
• disease-modifying anti-rheumatic drugs (DMARDs)

Some people may be given other medicines that block chemicals which activate the immune system. These are known as biological medicines. But you will usually be given DMARDs to try first.

For most people, this means trying many different medicines before finding what suits them. Some of these can also treat psoriasis.

If you have psoriatic arthritis, you may be more likely to get some other conditions, as happens with psoriasis and other types of inflammatory arthritis. One of these is cardiovascular disease (CVD), which is the term for conditions of the heart or blood vessels, such as heart disease and stroke.

Your doctor should carry out tests each year, such as blood pressure and cholesterol tests, so they can check whether you have CVD. They may offer additional treatment if you need it.

Psoriatic arthritis can also cause inflammation of the eyes, such as conjunctivitis and iritis.

If psoriatic arthritis affects both your skin and your joints, you may notice changes in your nails, such as:

• dents
• pits
• discolouration
• loosening from the nail bed

This is less common if only your skin is affected.

Along with your doctor and a rheumatologist, you may also be cared for by other specialists:

• a specialist nurse, who is often your first point of contact with your specialist care team
• a dermatologist (skin specialist), who is responsible for treating psoriasis symptoms
• a physiotherapist, who can create an exercise plan to keep your joints mobile
• an occupational therapist, who can help you overcome difficulties in your everyday life
• a psychologist, who can offer psychological support if you need it
• a podiatrist, who can offer assessment and advice on foot problems

Psoriatic arthritis is a long-term condition. When it affects many joints, you will likely need regular treatment to keep the disease under control.

If it is diagnosed early and treated properly, psoriatic arthritis can progress more slowly. Treatment can also reduce permanent damage to your joints, or prevent it.

In some people with severe disease, the joints may become permanently damaged or deformed, and surgery is then needed.

You can help yourself too, by:

• having a good balance between rest and regular physical activity
• losing weight, if you're overweight
• not smoking
• only drinking moderate amounts of alcohol

Losing weight helps your general health and takes some strain off your joints. There's evidence that it can also improve the control of psoriatic arthritis and help you respond better to treatment.

Several studies have shown that people with psoriatic arthritis who don't smoke tend to have less severe disease. They also respond much better to treatment than those who do smoke.