PassFinals
Musculoskeletal

Psoriatic arthritis

A heterogeneous inflammatory arthritis associated with psoriasis, characterised by combinations of peripheral arthritis, axial disease, enthesitis, dactylitis and nail involvement.

In a nutshell

Psoriatic arthritis is a heterogeneous seronegative inflammatory arthritis associated with psoriasis, with combinations of peripheral arthritis, axial disease, enthesitis, dactylitis and nail disease. Early rheumatology referral and phenotype-led treatment protect function.

Classic presentation

Inflammatory arthritis with psoriasis or family history, nail pitting, dactylitis, enthesitis or distal interphalangeal involvement.

Key points

  • Psoriatic arthritis may precede visible psoriasis, so examine the skin and nails and ask about family history.
  • Disease domains include peripheral joints, axial skeleton, entheses and digits.
  • PEST can screen adults with psoriasis but does not detect axial disease or inflammatory back pain.
  • A hot joint needs urgent exclusion of septic or crystal arthritis.
  • Use conventional DMARDs mainly for persistent peripheral disease and specialist biologic or targeted therapy for active disease not controlled by initial treatment.
  • Coordinate treatment with dermatology, gastroenterology and ophthalmology when skin, bowel or eye disease is present.

First-line investigation

Clinical joint, skin and nail assessment with PEST where appropriate, inflammatory markers, targeted serology and imaging selected by phenotype.

Management

Recognise and refer

  • Refer suspected psoriatic arthritis to rheumatology and document peripheral, axial, entheseal, dactylitic, skin and nail domains; exclude a hot-joint emergency.1,2

Control symptoms and function

  • Use risk-assessed NSAID treatment, local steroid where appropriate, exercise, physiotherapy, occupational therapy and joint protection.2,3

Treat persistent peripheral disease

  • Use a rheumatology-directed conventional DMARD for persistent peripheral arthritis, selecting treatment around skin disease, comorbidity and patient priorities.1,2,3

Use phenotype-led advanced therapy

  • Select current NICE-approved biologic or targeted therapy according to joint domains, skin, bowel and eye disease, with specialist infection screening and monitoring.1,2,3

Review the whole disease burden

  • Monitor joint activity, function, skin, nails, bowel and eye symptoms, cardiovascular risk, fatigue and treatment toxicity; revise the plan when a new domain emerges.1,2

Exam traps

  • Psoriatic arthritis can precede psoriasis.
  • PEST does not detect axial arthritis or inflammatory back pain.
  • DIP disease and nail psoriasis support the diagnosis but are not individually diagnostic.
  • A positive rheumatoid factor does not exclude psoriatic arthritis, and a negative result does not prove it.
  • Do not escalate immunosuppression before excluding septic arthritis in a hot joint.

Illustrations

Psoriatic nail and distal joint diseaseClinical photograph showing distal joint deformity and nail dystrophy in psoriatic arthritis.James Heilman, MD, Wikimedia Commons · CC-BY-SA-3.0
Pencil-in-cup deformityRadiograph showing the pencil-in-cup deformity of severe erosive psoriatic arthritis.Hellerhoff, Wikimedia Commons · CC-BY-SA-4.0

Key sources

  1. NICE CG153: Psoriasis: assessment and management (UK annual psoriatic arthritis assessment, PEST screening, rheumatology referral and coordinated systemic treatment guidance.)
  2. NICE NG65: Spondyloarthritis in over 16s: diagnosis and management (UK peripheral and axial spondyloarthritis referral, imaging, exercise and pharmacological pathway.)Updated 4 Mar 2025
  3. BNF online (Check current NSAID, DMARD, biologic and targeted therapy prescribing, interactions, contraindications, pregnancy and monitoring.)

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.