What is the recommended treatment for a patient with psoriatic arthritis?

Treatment of Psoriatic Arthritis

For patients with psoriatic arthritis, initiate a conventional synthetic DMARD (methotrexate preferred, especially with skin involvement) rapidly for polyarthritis, and advance to biologic therapy with TNF inhibitors, IL-17 inhibitors, or IL-12/23 inhibitors if inadequate response occurs after at least one DMARD trial. 1

Treatment Goals and Monitoring

• The primary objective is achieving remission or, alternatively, minimal/low disease activity through regular disease activity assessment and appropriate therapy adjustment 1, 2
• Target abrogation of inflammation as the critical component to maximize health-related quality of life, control symptoms, prevent structural damage, normalize function, and maintain social participation 1, 3
• Account for extra-articular manifestations, metabolic syndrome, cardiovascular disease, and other comorbidities when selecting treatment 1

Initial Symptomatic Management

• NSAIDs may be used to relieve musculoskeletal signs and symptoms but provide only symptomatic relief without preventing structural joint damage 1, 2
• Local glucocorticoid injections should be considered as adjunctive therapy for persistently inflamed joints 1, 2
• Systemic glucocorticoids may be used with caution at the lowest effective dose, but are not recommended for chronic use due to potential post-steroid psoriasis flare 1

Disease-Modifying Therapy Algorithm

For Polyarticular Disease:

• Initiate a conventional synthetic DMARD (csDMARD) rapidly, with methotrexate (15-25 mg weekly) preferred when clinically relevant skin involvement is present 1, 2
• Alternative csDMARDs include sulfasalazine (level A evidence) or leflunomide (level A evidence) 1, 2
• Methotrexate has level B evidence for peripheral arthritis but level A evidence when significant skin disease coexists 2, 4

For Monoarthritis or Oligoarthritis:

• Consider a csDMARD particularly when poor prognostic factors are present, including structural damage, elevated ESR/CRP, dactylitis, or nail involvement 1

Escalation to Biologic Therapy:

• In patients with inadequate response to at least one csDMARD (defined as >3 months treatment with >2 months at standard target dose), commence biologic DMARD (bDMARD) therapy 1
• When relevant skin involvement exists, IL-17 inhibitors or IL-12/23 inhibitors may be preferred over TNF inhibitors 1, 3
• TNF inhibitors (etanercept, adalimumab, infliximab) have level A evidence for inhibiting radiographic progression and improving symptoms, physical function, and quality of life 1, 2, 5, 6
• IL-12/23 inhibitors are particularly preferred if concomitant inflammatory bowel disease is present 3

Further Escalation Options:

• In patients with 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 1
• For mild disease with inadequate response to at least one csDMARD where neither bDMARD nor JAK inhibitor is appropriate, a PDE4 inhibitor may be considered 1
• When switching biologics, consider one switch within a class before changing to a different mechanism of action 1

Special Clinical Scenarios

Enthesitis:

• For unequivocal enthesitis with insufficient response to NSAIDs or local glucocorticoid injections, therapy with a bDMARD should be considered 1

Predominantly Axial Disease:

• For active axial disease with insufficient response to NSAIDs, therapy with a bDMARD should be considered, which according to current practice is a TNF inhibitor 1
• When relevant skin involvement exists, IL-17 inhibitors may be preferred 1
• Traditional oral DMARDs (methotrexate, leflunomide, sulfasalazine) have not been shown effective for axial manifestations and are not recommended for axial disease 1

Critical Safety Considerations

TNF Inhibitor Warnings:

• Patients are at increased risk for serious infections including tuberculosis reactivation, invasive fungal infections, and opportunistic infections 5, 6
• Test for latent tuberculosis before initiating TNF inhibitors and periodically during therapy; initiate treatment for latent infection prior to TNF inhibitor use 5, 6
• Discontinue if serious infection or sepsis develops 5
• Lymphoma and other malignancies have been reported, particularly hepatosplenic T-cell lymphoma in adolescent and young adult males receiving concomitant azathioprine or 6-mercaptopurine 6

Contraindications and Cautions:

• Avoid methotrexate as first-line in patients with concomitant diabetes due to higher risk of fatty liver disease and hepatotoxicity 2
• In patients with frequent serious infections, congestive heart failure, demyelinating disease, or recurrent infections, oral small molecules are preferred over biologics 2
• Gold salts, chloroquine, and hydroxychloroquine are not recommended for PsA 1

Combination Therapy Considerations

• Methotrexate, glucocorticoids, NSAIDs, and/or analgesics may be continued during treatment with biologics 5, 6
• TNF inhibitors can be used as monotherapy or combined with methotrexate at reduced doses (10-15 mg weekly) 2
• Although no strong evidence exists for combination csDMARD therapy, it could be used in patients who fail single agents or present joint damage progression despite treatment 1

Treatment De-escalation

• In patients achieving sustained remission, cautious tapering of DMARDs may be considered 1

Common Pitfalls to Avoid

• Do not use NSAIDs as sole therapy beyond 3 months if disease remains active, as they do not prevent structural damage 2
• Do not delay csDMARD initiation in polyarticular disease—rapid initiation is essential 1, 2
• Do not continue an inadequate csDMARD trial beyond the defined failure criteria (>3 months with >2 months at target dose) before escalating to biologics 1
• Do not overlook screening for latent tuberculosis before initiating biologic therapy 5, 6