Synopsis
Screen every person with psoriasis for peripheral and axial musculoskeletal disease, understand PEST limitations, identify urgent mimics, and refer suspected psoriatic arthritis before structural damage accumulates.
- Offer annual psoriatic arthritis assessment to everyone with psoriasis, especially during the first ten years after psoriasis begins, and reassess whenever musculoskeletal symptoms change.
- Ask about swollen joints, morning stiffness, dactylitis, heel or other enthesis pain and inflammatory back pain; examine rather than relying on the word arthritis.
- Use a validated adult tool such as PEST in primary and specialist care, but remember that PEST does not detect axial arthritis or inflammatory back pain.
- A positive screen is not a diagnosis and a negative score is not exclusion; the clinical pattern determines referral.
- NICE says refer to rheumatology as soon as psoriatic arthritis is suspected; do not wait for radiographic erosions, elevated CRP or dermatology review.
- Urgently refer suspected new inflammatory arthritis under the NICE spondyloarthritis pathway; dactylitis and persistent or multisite non-mechanical enthesitis also merit rheumatology assessment.
- Check mimics and emergencies in parallel: septic arthritis, gout or CPP crystal arthritis, rheumatoid arthritis, mechanical pain and fibromyalgia require different pathways.
- Record skin and nail phenotype, family history, uveitis, inflammatory bowel disease, recent infection, medicines, smoking, cardiovascular risk and the person's functional priorities.
- Psoriatic arthritis has no single confirmatory blood test: rheumatoid-factor status, HLA-B27, inflammatory markers and imaging answer selected differential questions but do not replace pattern recognition.
Key red flags
A hot, very painful swollen joint with fever, rigors or immunosuppression is septic arthritis until urgently assessed and sampled.
A painful red photophobic eye or sudden visual change may be acute anterior uveitis and requires same-day ophthalmological assessment.
New weakness, saddle sensory change, sphincter disturbance or rapidly progressive neurological deficit with back pain requires an emergency spinal pathway.
Marked functional loss, rapidly progressive polyarthritis or inability to weight-bear warrants urgent clinical assessment even when routine inflammatory markers are normal.
Persistent swelling, pain and stiffness may be asymmetric, oligoarticular or polyarticular. Morning stiffness and improvement with movement support inflammation, but examine for synovitis rather than using duration alone.
Uniform swelling and tenderness of an entire finger or toe creates a sausage digit and reflects combined joint and tendon-sheath inflammation. NICE recommends rheumatology referral for dactylitis.
Eye pain, redness, photophobia and blurred vision in a spondyloarthritis context needs same-day ophthalmology; conjunctivitis is usually gritty rather than deeply painful or photophobic.
Investigation priorities
Identify peripheral synovitis, dactylitis, enthesitis and axial features in every person with psoriasis.
Management branches
Any person with psoriasis, regardless of current skin severity or treatment.
- Ask about new or recurrent joint swelling, morning stiffness, whole-digit swelling, heel pain and back or buttock pain with night waking or improvement on movement.
- Use PEST in adults, then deliberately add axial questions because the tool does not assess inflammatory back pain.
- Examine joints, digits, entheses, spine movement where relevant, skin and nails; record function, duration, family history, uveitis and inflammatory bowel disease.
- If there is no current suspicion, document the screen and repeat annually or sooner when symptoms change, explaining which symptoms should prompt review.