Quick answer. Psoriatic arthritis is an autoimmune form of arthritis linked to the skin condition psoriasis, causing joint pain and swelling along with skin and nail changes. Early treatment by a rheumatologist, including biologic medicines when needed, helps prevent lasting joint damage.
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Psoriatic arthritis (PsA) is a chronic inflammatory arthritis that occurs in some people who have psoriasis, a condition that causes scaly, reddish skin patches. The immune system attacks the joints and the places where tendons and ligaments attach to bone, leading to pain, stiffness and swelling. It can also affect the spine, fingers, toes and nails.
Most people develop the skin psoriasis first, sometimes years before the joints become involved, but occasionally the arthritis comes first. Because untreated PsA can cause permanent joint damage, early recognition and assessment by a rheumatologist are key.
At a glance
| Area | What to look for | Notes |
|---|---|---|
| Skin | Scaly red or silvery patches on scalp, elbows, knees or behind ears | Psoriasis usually appears before the arthritis |
| Nails | Pitting, discolouration, thickening or lifting of the nail | Nail changes are very common in psoriatic arthritis |
| Fingers & toes | A whole finger or toe swollen like a sausage (dactylitis) | A classic and useful clue to the diagnosis |
| Joints | Pain, swelling and morning stiffness, sometimes uneven between sides | Can affect small joints, large joints or the spine |
| Tendons | Pain at the heel or sole of the foot (enthesitis) | Inflammation where tendons attach to bone |
The link between psoriasis and arthritis
Psoriasis and psoriatic arthritis are part of the same underlying immune condition. A significant minority of people with skin psoriasis go on to develop joint inflammation. The severity of the skin disease does not reliably predict who will get arthritis, and some people with very mild skin patches develop significant joint problems.
If you have psoriasis and notice persistent joint pain, stiffness or swelling, tell your doctor. Skin specialists (dermatologists) and rheumatologists often work together, as treating both the skin and the joints gives the best results.
Joint, skin and nail signs to watch for
Psoriatic arthritis can look different from person to person. Common features include:
- Joint symptoms – pain, swelling and stiffness, often worse in the morning, which may affect the fingers, toes, knees, ankles or lower back.
- Dactylitis – swelling of an entire finger or toe, giving a ‘sausage digit’ appearance.
- Enthesitis – pain where tendons attach to bone, such as the heel (Achilles tendon) or sole of the foot.
- Nail changes – pitting, discolouration, thickening or separation of the nail, which are common in PsA.
Back pain that is worse with rest and better with movement can indicate spinal involvement and should be assessed.
How psoriatic arthritis is diagnosed
There is no single blood test for psoriatic arthritis. A rheumatologist makes the diagnosis based on your symptoms, a careful examination of the joints, skin and nails, and your history of psoriasis. Investigations may include:
- Blood tests to check for inflammation and to help rule out other types of arthritis such as rheumatoid arthritis or gout.
- X-rays, ultrasound or MRI to look for joint inflammation and early damage.
Because PsA can be confused with other joint conditions, specialist assessment is important to confirm the diagnosis and start the right treatment early.
Why early treatment matters
Inflammation in psoriatic arthritis can gradually damage joints, and once damage has occurred it cannot be reversed. Treating the disease early, before significant damage develops, gives the best chance of controlling symptoms and preserving joint function.
This is sometimes called a ‘treat to target’ approach, where treatment is adjusted until inflammation is well controlled. Regular follow-up allows your rheumatologist to step treatment up or down as needed.
Treatment options, including biologics
Treatment is tailored to how many joints are affected, whether the spine or skin is involved, and how severe the disease is. Options include:
- NSAIDs (anti-inflammatory painkillers) for milder joint symptoms.
- Conventional DMARDs such as methotrexate, sulfasalazine or leflunomide, which dampen the immune attack.
- Biologic therapies (for example TNF inhibitors, IL-17 or IL-23 inhibitors) for more active disease that does not respond to standard medicines; these target specific parts of the immune system and can be very effective for both joints and skin.
- Targeted oral medicines such as JAK inhibitors in selected cases.
Biologics require screening (for example for tuberculosis and hepatitis) and monitoring, as they can increase infection risk. Exercise, weight management and physiotherapy support the medical treatment.
When to see a rheumatologist (red flags)
If you have psoriasis and develop joint pain, swelling, prolonged morning stiffness, a ‘sausage’ finger or toe, heel pain, or new nail changes, see a doctor and ask about referral to a rheumatologist. Early assessment is especially important if symptoms are persistent or getting worse.
Do not wait for joints to become deformed before seeking help. Seek prompt care if a joint becomes hot, red and very painful, or if you develop fever with joint swelling, as this needs urgent evaluation to exclude infection.
How to prepare for your appointment
Bring as full a picture as you can. Note when your skin psoriasis started, where the patches are and how the joint symptoms have behaved over time. Photographs of swollen ‘sausage’ fingers or toes, flares or nail changes are useful, as these can come and go. List the joints that hurt or swell, how long morning stiffness lasts, and any heel or foot pain. Record all medicines and creams you use, and mention any family history of psoriasis, arthritis or inflammatory bowel disease. If you already see a dermatologist for your skin, it helps to share their notes, since coordinated care of skin and joints tends to give the best results.
Self-management at home
Alongside medical treatment, daily choices support your joints and skin. Regular low-impact exercise such as swimming or cycling helps keep joints mobile without jarring them, and maintaining a healthy weight reduces load on the lower limbs and may improve how well treatment works. Continue caring for your skin as advised, and protect joints during flares by pacing activity and using larger joints for heavy tasks. Stopping smoking and limiting alcohol can benefit both skin and joints.
Common questions
Can psoriatic arthritis be cured?
There is no cure, but it can usually be well controlled. Treating it early, before joint damage develops, gives the best chance of preserving function, which is why a ‘treat to target’ approach is used.
Are there subsidies for treatment?
Psoriasis is recognised under the Chronic Disease Management Programme, but psoriatic arthritis is a distinct diagnosis, so financing depends on your specific situation and care setting. Ask your clinic which subsidies, schemes or public options may apply, especially as biologic medicines can be expensive.
Related guides
- Best Rheumatology Clinics in Singapore — our editorial shortlist
- rheumatology clinics directory
- Lupus (SLE)
- Ankylosing Spondylitis
- Fibromyalgia
Sources
- SingHealth – Psoriatic Arthritis
- SGH – Rheumatology and Immunology
- MOH – Chronic Disease Management Programme (CDMP)
- HealthHub – MediSave for Chronic Disease Management
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