What is the initial treatment approach for patients with psoriatic arthritis?

Initial Treatment Approach for Psoriatic Arthritis

For treatment-naive patients with active psoriatic arthritis, initiate a TNF inhibitor biologic as first-line therapy over conventional synthetic DMARDs, based on the most recent American College of Rheumatology recommendations. 1

However, this recommendation conflicts with European guidance and requires careful consideration of disease presentation and patient factors.

Treatment Algorithm Based on Disease Pattern

For Polyarticular Disease (Multiple Joint Involvement)

• Start with a conventional synthetic DMARD (csDMARD) rapidly, with methotrexate preferred when significant skin involvement is present. 2, 1
• Methotrexate should be initiated at 15-25 mg weekly with folic acid supplementation in patients with concomitant skin disease. 3
• If inadequate response after at least 3 months, escalate to a biologic DMARD, specifically a TNF inhibitor such as adalimumab, etanercept, or infliximab. 1, 3
• Alternative csDMARDs include sulfasalazine (level A evidence) or leflunomide (level A evidence) when methotrexate is contraindicated. 3, 4

For Oligoarthritis or Monoarthritis

• NSAIDs may be used initially to relieve musculoskeletal signs and symptoms. 2
• Consider initiating a csDMARD if poor prognostic factors are present: structural damage, high ESR/CRP, dactylitis, or nail involvement. 2, 1
• Local glucocorticoid injections should be considered as adjunctive therapy for persistently inflamed joints. 2, 3

For Predominantly Axial Disease

• Start with NSAIDs and physiotherapy as initial management. 3
• For active axial disease with insufficient response to NSAIDs, initiate a TNF inhibitor biologic. 2, 1
• When relevant skin involvement exists, an IL-17 inhibitor may be preferred over TNF inhibitors. 2, 3

For Enthesitis

• Mild cases: NSAIDs and local corticosteroid injections. 1, 3
• For insufficient response to NSAIDs or local injections, initiate a biologic DMARD (TNF inhibitor). 2, 1

Critical Treatment Principles

• Treatment must aim for remission or, alternatively, low disease activity through regular disease activity assessment and appropriate therapy adjustment. 2, 1
• Do not delay DMARD initiation in patients with polyarthritis or poor prognostic factors, as early treatment improves long-term outcomes. 1
• Systemic glucocorticoids may be used cautiously at the lowest effective dose for short-term management, but are not recommended for chronic use due to risk of post-steroid psoriasis flare. 1, 3

Escalation Pathway for Inadequate Response

• After failure of at least one csDMARD, initiate a biologic DMARD (bDMARD), preferably a TNF inhibitor. 2, 1
• When there is relevant skin involvement, IL-17 inhibitors or IL-12/23 inhibitors may be preferred over TNF inhibitors. 2
• After inadequate response to at least one csDMARD and at least one bDMARD, or when a bDMARD is not appropriate, a JAK inhibitor may be considered. 2, 3
• For mild disease with inadequate response to at least one csDMARD, where neither a bDMARD nor JAK inhibitor is appropriate, a PDE4 inhibitor (apremilast) may be considered. 2

Special Populations and Contraindications

• In patients with concomitant diabetes, use sulfasalazine or leflunomide instead of methotrexate due to higher risk of fatty liver disease and hepatotoxicity. 3
• In patients with frequent serious infections, oral small molecules are strongly recommended over biologics as first-line treatment. 3
• In patients with contraindications to biologics (congestive heart failure, demyelinating disease, recurrent infections), csDMARDs are recommended. 3

Common Pitfalls to Avoid

• Do not use methotrexate as first-line in diabetic patients - select alternative csDMARDs like sulfasalazine or leflunomide. 3
• Avoid injecting glucocorticoids through psoriatic plaques. 3
• Do not delay escalation to biologics after 3 months of inadequate csDMARD response in patients with active disease. 1
• NSAIDs provide only symptomatic relief and do not prevent structural joint damage - they are not adequate monotherapy for moderate to severe disease. 3

Monitoring and Safety Considerations

• Test patients for latent tuberculosis before initiating TNF inhibitors and during therapy; initiate treatment for latent TB prior to TNF inhibitor use. 5
• Monitor closely for development of infections during and after treatment with biologics. 5
• Be aware of increased risk of lymphoma and other malignancies with TNF blockers, particularly hepatosplenic T-cell lymphoma in young males receiving concomitant azathioprine or 6-mercaptopurine. 5