What is the recommended treatment for a patient with concurrent streptococcal (strep) pharyngitis and influenza (flu) who has had flu symptoms for 5 days?

Treatment of Concurrent Streptococcal Pharyngitis and Influenza

Treat the streptococcal pharyngitis with standard antibiotics (penicillin or amoxicillin for 10 days) but do NOT initiate antiviral therapy for influenza at 5 days post-symptom onset, as the window for effective treatment has closed.

Influenza Management at Day 5

• Antiviral therapy is NOT recommended because the patient is beyond the 48-hour window from symptom onset when neuraminidase inhibitors provide meaningful benefit 1
• Guidelines specify that individuals should only be considered for antiviral treatment if they have been symptomatic for two days or less 1
• The standard treatment schedule for influenza is oseltamivir 75 mg every 12 hours for five days, but this is only effective when started within 48 hours 1, 2
• Exception: Hospitalized patients who are severely ill, particularly if immunocompromised, may benefit from antiviral treatment started more than 48 hours from disease onset, though evidence is lacking 1

Streptococcal Pharyngitis Treatment

• First-line therapy: Penicillin or amoxicillin for 10 days 3
• For penicillin-allergic patients (non-anaphylactic): First-generation cephalosporins 3
• Avoid azithromycin and clarithromycin as first-line agents due to significant resistance in some U.S. regions 3
• The positive strep test confirms bacterial infection requiring antibiotic therapy regardless of concurrent viral illness 3

Critical Clinical Considerations

Antibiotic Selection in Dual Infection Context

• Standard streptococcal pharyngitis antibiotics (penicillin/amoxicillin) do NOT provide coverage for influenza-related bacterial complications 1
• Do not routinely add broader antibiotics for uncomplicated influenza without pneumonia, even in the presence of strep pharyngitis 1, 4
• Consider broader coverage (co-amoxiclav or tetracycline) only if the patient develops worsening symptoms suggesting influenza-related pneumonia: recrudescent fever or increasing dyspnea 1

Monitoring for Complications

• Re-evaluate if strep symptoms worsen after 5 days of appropriate antibiotic therapy 3
• Watch for signs of influenza-related bacterial superinfection, which typically develops 4-5 days after initial influenza symptoms 4:
  • New or worsening fever after initial improvement
  • Increasing dyspnea or respiratory distress
  • Purulent sputum production
  • Signs of pneumonia on examination

Common Pitfalls to Avoid

• Do not prescribe oseltamivir at day 5 simply because the patient has confirmed influenza—the therapeutic window has closed and benefit is negligible 1, 2
• Do not withhold strep antibiotics due to concurrent influenza; bacterial pharyngitis requires treatment regardless of viral co-infection 3
• Do not empirically broaden antibiotic coverage beyond what strep pharyngitis requires unless specific signs of pneumonia or bacterial superinfection develop 1, 4
• Do not use zanamivir if the patient has any underlying airways disease, as it carries risk of life-threatening bronchospasm 5, 6, 7

Supportive Care

• Antipyretics and fluids for symptomatic relief 1
• Aspirin should not be used in children due to Reye's syndrome risk 1
• Patients should be counseled that influenza symptoms may persist for several more days despite being beyond the antiviral treatment window 2, 8