What treatment is recommended for a patient with systemic lupus erythematosus (SLE) who has contracted influenza B?

Treatment of Influenza B in Patients with Systemic Lupus Erythematosus

Treat influenza B infection in SLE patients with standard antiviral therapy (oseltamivir 75 mg twice daily for 5 days) while maintaining their baseline immunosuppressive regimen, as there is no evidence requiring modification of SLE treatment during acute influenza infection. 1

Antiviral Treatment Approach

• Administer oseltamivir phosphate 75 mg orally twice daily for 5 days, initiated as soon as possible after symptom onset, ideally within 48 hours 1
• Oseltamivir has demonstrated efficacy in immunocompromised patients, including solid organ and hematopoietic stem cell transplant recipients, with confirmed clinical influenza rates of 2% in treated patients versus 3% in placebo 1
• The drug is FDA-approved and has established safety profiles in immunocompromised populations 1

Management of Baseline SLE Therapy During Acute Infection

• Continue hydroxychloroquine (≤5 mg/kg real body weight) without interruption, as this foundational therapy should not be discontinued during acute infections 2, 3
• Maintain current glucocorticoid doses initially; do not empirically increase steroids unless there is evidence of lupus flare distinct from influenza symptoms 2, 4
• Continue baseline immunosuppressive agents (methotrexate, azathioprine, mycophenolate) unless severe sepsis develops 5, 2

Critical Monitoring for Complications

• Aggressively monitor for bacterial superinfection and sepsis, as SLE patients have 5-fold increased mortality risk from infections, particularly those on high-dose glucocorticoids, cyclophosphamide, mycophenolate, or rituximab 5, 3
• Use validated sepsis scores (quick SOFA: systolic BP ≤100 mmHg, respiratory rate ≥22/min, altered mental status with Glasgow coma scale <15) to identify patients requiring intensive monitoring 5
• Watch specifically for hemophagocytic syndrome, a rare but documented complication of influenza B in SLE patients that presents with fever, cytopenias, and elevated ferritin 6

Distinguishing Influenza from Lupus Flare

• Influenza B typically presents with acute onset fever, cough, coryza, and myalgias within 24-48 hours 1
• If constitutional symptoms persist beyond 7-10 days or new organ-specific manifestations develop (nephritis, serositis, cytopenias), assess for lupus flare with complement levels (C3, C4), anti-dsDNA antibodies, complete blood count, urinalysis, and validated disease activity indices 5, 3
• The case report of influenza B-associated hemophagocytic syndrome and pericarditis demonstrates that severe complications may require steroid pulse therapy (methylprednisolone 500-1000 mg/day for 3 days), but this should only be initiated after confirming lupus activity rather than isolated viral infection 6, 4

Prevention Considerations for Future Seasons

• Annual influenza vaccination is strongly recommended for all SLE patients, as it reduces confirmed clinical influenza despite somewhat lower immunogenicity compared to healthy controls 5, 7
• Vaccination should be administered during stable disease, preferably before starting or at least 6 months after rituximab therapy, as B-cell depletion severely impairs vaccine responses 5
• Immune responses to influenza B strains are better preserved in SLE patients compared to influenza A strains, with meta-analyses showing SLE patients meet standard immunogenicity thresholds for influenza B protection 5
• Azathioprine may reduce vaccine response but the majority of patients still develop protective antibody levels 5

Common Pitfalls to Avoid

• Do not delay oseltamivir initiation while awaiting laboratory confirmation of influenza type, as clinical benefit is greatest when started within 48 hours of symptom onset 1
• Do not empirically increase immunosuppression for fever alone without evidence of lupus flare, as this increases infection risk 5
• Do not discontinue hydroxychloroquine during acute infection, as this foundational therapy improves survival and should only be stopped for true contraindications 2, 3
• Do not assume all constitutional symptoms represent lupus flare in flu season; influenza can cause significant systemic symptoms that resolve with antiviral therapy alone 6