Psoriatic arthritis is a type of arthritis that develops in some people with the skin condition psoriasis. It typically causes affected joints to become inflamed (swollen), stiff and painful.
Like psoriasis, psoriatic arthritis is a long-term condition that can get progressively worse. In severe cases, there's a risk of the joints becoming permanently damaged or deformed, which may require surgical treatment.
However, with an early diagnosis and appropriate treatment, it's possible to slow down the progression of the condition and minimise or prevent permanent damage to the joints.
Symptoms of psoriatic arthritis
The pain, swelling and stiffness associated with psoriatic arthritis can affect any joint in the body, but the condition often affects the hands, feet, knees, neck, spine and elbows.
The severity of the condition can vary considerably from person to person. Some people may have severe problems affecting many joints, whereas others may only notice mild symptoms in 1 or 2 joints.
There may be times when your symptoms improve (known as remission) and periods when they get worse (known as flare-ups or relapses).
Relapses can be very difficult to predict, but can often be managed with medication when they do occur.
When to seek medical advice
See your GP if you experience persistent pain, swelling or stiffness in your joints – even if you haven't been diagnosed with psoriasis.
If you've been diagnosed with psoriasis, you should have check-ups at least once a year to monitor your condition. Make sure you let your doctor know if you're experiencing any problems with your joints.
Causes of psoriatic arthritis
Between 1 and 2 in every 5 people with psoriasis develop psoriatic arthritis.
It usually develops within 10 years of psoriasis being diagnosed, although some people may experience problems with their joints before they notice any symptoms affecting their skin.
Like psoriasis, psoriatic arthritis is thought to occur as a result of the immune system mistakenly attacking healthy tissue.
However, it's not clear why some people with psoriasis develop psoriatic arthritis and others don't.
Diagnosing psoriatic arthritis
If your doctor thinks you may have arthritis, they should refer you to a rheumatologist (a specialist in joint conditions) for an assessment.
A rheumatologist will usually be able to diagnose psoriatic arthritis if you have psoriasis and problems with your joints.
They'll also try to rule out other types of arthritis, such as rheumatoid arthritis and osteoarthritis.
A number of tests may be carried out to help confirm a diagnosis, including:
blood tests to check for signs of inflammation in your body and the presence of certain antibodies found in other types of arthritis
X-rays or scans of your joints
Treating psoriatic arthritis
The main aims of treatment will be to relieve your symptoms, slow the progression of the condition and improve your quality of life.
Biological treatments are a newer form of treatment for psoriatic arthritis. You may be offered one of these treatments if:
your psoriatic arthritis hasn't responded to at least two different types of DMARD
you're not able to be treated with at least two different types of DMARD
Biological drugs work by stopping particular chemicals in the blood from activating your immune system to attack the lining of your joints.