Synopsis
Recognise the diverse peripheral, entheseal, dactylitic and axial patterns of psoriatic arthritis, coordinate skin and joint priorities, and escalate disease-modifying treatment according to the dominant active domain.
- Psoriatic arthritis may present as asymmetric oligoarthritis, symmetrical polyarthritis, DIP disease, dactylitis, enthesitis or axial inflammation; actively search all domains.
- Psoriasis may be subtle or appear after arthritis, so inspect scalp, umbilicus, natal cleft, ears and nails and ask about family history.
- Dactylitis is whole-digit inflammation and enthesitis affects insertion sites; neither is captured reliably by a standard rheumatoid joint count.
- RF can be positive incidentally and no blood test confirms PsA; diagnosis rests on phenotype and exclusion of infection and crystals.
- Treat active peripheral arthritis promptly with a conventional DMARD such as methotrexate, leflunomide or sulfasalazine under rheumatology care; choose according to skin, comorbidity and pregnancy factors.
- Persistent active disease may require TNF, IL-17, IL-23, PDE4, JAK or other targeted therapy selected for the dominant joint, axial, entheseal and skin domains. Recurrent uveitis or active bowel disease materially constrains class choice.
- Avoid using systemic corticosteroids casually because metabolic, infection and psoriasis risks can outweigh transient benefit; local injection still requires infection exclusion.
- Address weight, smoking, cardiovascular risk, mood, work and treatment adherence as core disease management rather than optional additions.
Key red flags
One abruptly hot restricted joint, fever or immunosuppression requires aspiration and culture even when established PsA explains other symptoms.
Painful red photophobic eye, significant bowel activity or severe skin disease may determine urgency and the safest shared treatment choice.
Investigation priorities
Define peripheral, entheseal, dactylitic, axial and cutaneous disease domains.
Management branches
Persistent peripheral synovitis, dactylitis or function-limiting inflammatory disease accompanies psoriasis or a strong psoriatic phenotype.
- Document joints, digits, entheses, skin, nails, axial, eye and bowel features and obtain treatment-safety baseline bloods and infection assessment.
- Refer promptly to rheumatology and coordinate dermatology; begin a conventional DMARD for active peripheral arthritis according to shared domain priorities and contraindications.
- Set an objective review interval and escalate if the target is missed rather than continuing ineffective therapy while damage accumulates.
Key medicines
Methotrexate with folic acidUsually 7.5–15 mg once weekly initially, titrated by rheumatology within the product-specific maximum; record one fixed dosing day and prescribe folic acid at least 5 mg once weekly on a different day.Never prescribe or take it daily. Obtain risk-based FBC, liver and renal monitoring and review alcohol, lung and interacting-drug risks, especially trimethoprim or co-trimoxazole. Withhold it through a serious infection until recovered and reviewed. For maternal exposure, low-dose methotrexate must be stopped at least 1 month before planned conception and is not compatible with pregnancy or breastmilk exposure; accidental pregnancy needs immediate cessation, folic acid 5 mg/day and specialist fetal-risk review. BSR regards paternal exposure at no more than 25 mg/week as compatible; arrange specialist pre-conception planning.
AdalimumabThe usual adult psoriatic-arthritis regimen is 40 mg subcutaneously every other week under specialist prescribing and product information.Do not start during active tuberculosis or another serious infection; screen for TB and hepatitis B, and review demyelinating disease. It is contraindicated in NYHA III or IV heart failure and should stop for new or worsening failure. Give no live vaccine during therapy. If continued beyond 28 weeks of pregnancy, BSR advises deferring infant live vaccines until 6 months.