Psoriatic arthritis

Also called PsA

Arthritis that comes with psoriasis, often years after the skin. Joint damage is preventable, and delay is what causes it.

What it is

An inflammatory arthritis affecting around one in three people with psoriasis. The skin usually comes first, sometimes by a decade, and occasionally the joints come first.

It is not wear and tear. It is the immune system attacking joints, tendon insertions and the spine, and untreated it causes permanent damage within the first two years.

That timescale is why the diagnostic delay matters so much. Psoriasis is treated by dermatology, joint pain by a GP, and nobody is watching the join. People are commonly told it is osteoarthritis or back pain for years.

Treatment now is good. Early disease-modifying drugs and biologics prevent most of the damage, which makes early referral one of the highest-value referrals in this library.

Signs you might notice

Joint pain and swelling, often asymmetric, and often in the fingers and toes.

A whole finger or toe swollen like a sausage, rather than a single knuckle. This is dactylitis and it is close to specific for this condition.

Pain and stiffness in the lower back and buttocks, worse in the morning and after rest, better with movement. See ankylosing spondylitis.

Pain at tendon insertions, especially the heel.

Nail changes: pitting, ridging, thickening, or the nail lifting off the bed. Nail psoriasis carries a materially higher risk of this arthritis.

Fatigue that is out of proportion to the joint findings.

How it can affect day-to-day life

The fatigue is generally the part people rate as worst, and the part least often asked about.

The skin and the joints do not track each other, so mild psoriasis with severe arthritis is common, and being told the skin looks fine is not reassurance about the joints.

Working with painful hands and feet is exhausting in ways that do not show, and adjustments are usually small: voice input, a different keyboard, different shoes, not standing for a whole shift.

Depression and cardiovascular risk are both raised in this condition, and both are routinely missed while attention stays on the joints.

Supporting someone well

If somebody has psoriasis and joint pain, say the words psoriatic arthritis to the GP and ask for rheumatology referral. Do not wait to see whether it settles.

Ask for a screening questionnaire at psoriasis appointments; dermatology services are expected to look for this and often do not.

Take the disease-modifying treatment consistently. It is preventing damage that cannot be undone, not managing today's pain.

Ask about physiotherapy early, particularly for the spine and the heel.

Watch for eye pain, redness and light sensitivity. Uveitis goes with this family of conditions and needs same-day eye assessment.

Ask for cardiovascular risk to be reviewed, because it is higher and it is treatable.

Where to get help

A GP practice, asking directly for rheumatology referral.

Dermatology, if the person is already under them for skin.

PAPAA publish patient information on psoriasis and psoriatic arthritis together, which is unusual and useful.

Arthritis UK have a helpline and good self-management material.