Treatment of Psoriatic Arthritis in Patients with Latent Tuberculosis

Mandatory Pre-Treatment Screening

• The European League Against Rheumatism recommends tuberculosis screening for all patients with psoriatic arthritis being considered for biologic or immunosuppressive therapy, using the tuberculin skin test (TST) with induration ≥5 mm considered positive in immunosuppressed patients or those about to start immunosuppressive therapy 1, 2

Latent TB Prophylaxis Protocol

• The American Thoracic Society recommends isoniazid 300 mg daily for 9 months as the standard prophylactic regimen for latent TB, with prophylaxis started at least 1 month before biologic therapy when possible 2

Psoriatic Arthritis Treatment Selection

• The European League Against Rheumatism recommends conventional synthetic DMARDs (csDMARDs) such as methotrexate, sulfasalazine, or leflunomide as initial therapy for peripheral arthritis with latent TB, while awaiting TB clearance 1, 4
• The National Psoriasis Foundation recommends TNF inhibitors such as etanercept, adalimumab, or infliximab for inadequate response to csDMARDs, after adequate TB prophylaxis 1

Critical Safety Considerations for Biologics

• The Centers for Disease Control and Prevention recommends that tests for latent TB may be falsely negative while on TNF-blocker therapy, and induration of 5 mm or greater should be considered positive when assessing need for latent TB treatment prior to TNF inhibitors 2

Monitoring During Treatment

• The American College of Rheumatology recommends annual tuberculosis screening for patients on biologics 6

Evidence on Safety and Efficacy

• No relevant cited facts were found in this section

Critical Pitfalls to Avoid

• The Infectious Diseases Society of America recommends never adding a single drug to a failing TB treatment regimen, always add ≥2 drugs to prevent resistance 2
• The American Academy of Dermatology recommends not injecting glucocorticoids through psoriatic plaques, due to the risk of infection 3