Psoriatic Arthritis:
Treating Skin and Joints Together

1. What is psoriatic arthritis?

Psoriatic arthritis (PsA for short) is a chronic inflammatory joint disease that occurs together with psoriasis: the same misdirected immune reaction that forms plaques on the skin also turns against joints, tendon attachments and nails.^¹

Usually the skin comes first — often years before the first joints start to hurt. You cannot rely on that, though. In some people the joint symptoms begin at the same time or even before the skin, and sometimes the psoriasis is so inconspicuous (behind an ear, in the natal cleft, or nothing more than one altered nail) that it has never been noticed.^¹,²

Unlike osteoarthritis, in which cartilage wears down, what dominates here is active inflammation. That explains why movement does you good, why the symptoms are at their worst in the morning — and why, according to current knowledge, treatment started early can limit joint damage.^²

2. The typical patterns compared

PsA does not have a single face — it appears in several patterns, which can also occur alongside one another. Knowing them helps you put a name to your symptoms instead of dismissing them as “overuse”.^²,³

Rare is arthritis mutilans, with shortening of the fingers — an argument for early treatment. Also important: skin activity and joint activity do not run in parallel.

3. Symptoms and consequences

• Stiffness in the morning — typically more than 30 minutes before the joints get going.
• Improvement with movement — it gets better as the day goes on. With wear and tear it is usually the other way round.
• Pain at night and at rest — pain that wakes you in the second half of the night is a warning sign; the joint is often swollen and warm.
• Heel pain out of nowhere — if you have heel pain without new shoes or a jump in training, enthesitis is worth thinking about.
• Nail changes — brittle nails, pitting or separation are more than a cosmetic matter.

Left untreated, the inflammation can damage joints permanently. Lack of sleep, exhaustion and the burden of visible skin and nail changes count just as much — they belong in the conversation at your practice, even though they show up in no laboratory value. A first orientation: joint pain.

4. Causes and risk factors

According to current knowledge the cause has not been settled conclusively; an interplay of predisposition, the immune system and external triggers is assumed.^¹,³

• Existing psoriasis — the most important risk factor, particularly where nails are involved and where psoriasis sits in skin folds.
• Inherited predisposition — both conditions cluster in families.
• Excess weight — obesity counts as a risk factor and is linked to a poorer response to treatment.
• Smoking — puts a strain on vessels, skin and joints and can reduce the effect of some disease-modifying medicines.
• Strain, infections, stress — regarded as triggers of flares; the evidence is limited.

5. Diagnosis: why a blood test is not enough

There is no blood test that proves or rules out psoriatic arthritis. Rheumatoid factor, often positive in rheumatoid arthritis, is as a rule negative here — the condition belongs to the seronegative forms. CRP and the erythrocyte sedimentation rate can also be normal despite active inflammation. So an unremarkable blood result says nothing about whether your joints are inflamed.^³

• History: since when, which joints, stiff in the morning, better with movement? Psoriasis in you or in your family — even in just one small spot?
• Examination: counting swollen and tender joints, checking the tendon attachments, a look at nails, scalp, navel and natal cleft.
• Laboratory: CRP and sedimentation rate for activity, rheumatoid factor and CCP antibodies to tell it apart from other forms, kidney, liver and blood count values before treatment.
• Imaging: ultrasound shows effusion and inflammation at the tendon attachments, X-rays show the course, an MRI where involvement of the spine is suspected.

Telling it apart: what else can lie behind it

Rheumatoid arthritis typically affects the knuckles and the middle finger joints symmetrically, spares the end joints and more often comes with a positive rheumatoid factor. Gout starts at night, highly acutely and usually in a single joint — often the big toe. Osteoarthritis of the end joints looks similar, but causes pain on use rather than at rest, and knobbly thickening without bouts of swelling.

Take photos of the swollen fingers with you to the appointment, along with a list of all your medicines, including the ointments — more in Prepare for a doctor's appointment.

6. Treatment: the steps at a glance

The aim of treatment is the lowest possible inflammatory activity — in the skin, the joints, the tendon attachments and the nails at the same time. That is reached in steps, depending on how pronounced the disease is, which structures are affected and which other conditions are present. The decision is always made by your treating practice together with you.^²

7. Medicines from NSAIDs to biologics

NSAIDs: quick help with limits

Non-steroidal anti-inflammatory drugs such as ibuprofen or naproxen damp down pain and inflammation; naproxen lasts longer and is often preferred for pain at night. They do not influence the course of the disease. If you need them regularly over weeks, that is a signal to review the disease-modifying treatment — not a reason to raise the dose yourself. A side-by-side comparison: Painkillers compared.

Methotrexate: the weekly rule

Methotrexate is often the first disease-modifying medicine, because it addresses skin and joints at the same time. It is used as a tablet or a pre-filled syringe, as a rule once a week on the same day of the week, supplemented by folic acid taken at a separate time. Regular checks of blood count, liver and kidney values are usual, and alcohol is restricted.

Biologics: the infection risk

Biologics intervene in the immune system in a targeted way. That is what makes them effective — and it explains their most important side effect: a raised susceptibility to infections. Before starting, testing for hidden tuberculosis and for hepatitis is therefore usual. Afterwards the rule is: a fever or a persistent cough should be assessed promptly.^²,⁴

8. Taking accompanying conditions seriously

PsA is not purely a joint disease: lasting inflammation acts on the metabolism, and several accompanying conditions occur more frequently. Treating them alongside often does more for quality of life than a single swollen joint does.^¹,⁴

• Heart and vessels: the risk of coronary heart disease is raised where inflammation persists — blood pressure and cholesterol checks are part of the picture.
• Lipid metabolism and blood sugar: a lipid metabolism disorder goes unnoticed for a long time, and type 2 diabetes occurs more often.
• Weight: obesity increases disease activity and makes a good response to treatment harder.
• Eyes and bowel: uveitis and bowel conditions such as Crohn's disease belong to the same family of conditions and influence the choice of medicine.
• Exhaustion and mood: fatigue and low mood are common and are raised far too rarely.

9. Two practices, one medication plan

In hardly any other condition does treatment lie so naturally in two sets of hands: the skin with dermatology, the joints with rheumatology, and often the GP practice on top of that. The typical consequence: one practice starts a new systemic treatment without knowing which preparation the other one is using — or you are prescribed an NSAID while an over-the-counter painkiller has already been recommended elsewhere. This is where a complete medication plan is the connecting piece that otherwise goes missing.

• Include everything — ointments, shampoos, over-the-counter painkillers and food supplements too.
• Take the same version to both practices — that prevents duplicate modes of action. Instructions: Create a medication plan.
• Have combinations checked — NSAIDs with disease-modifying treatment or with blood pressure medicines deserve a look; see Drug interactions.

10. Everyday life with psoriatic arthritis

• Dose your activity, do not cancel it: cycling, swimming and targeted strength training are usually well tolerated. In a flare you reduce the load rather than stop moving — see Medications and exercise.
• Stopping smoking as a booster: the measure with the broadest benefit for skin, joints and vessels.
• Approach weight realistically: even a moderate reduction can have a favourable effect on disease activity and on the response to treatment.
• Diet: according to current knowledge there is no such thing as a “psoriasis diet”; a balanced diet is regarded as sensible, and alcohol is restricted on methotrexate.
• Do not sit flares out: if several joints stay swollen for days, that is a reason for an appointment.

Bring skin and rheumatology treatment together — with brite

One medication plan that both practices can see. Free.

Create a plan