What is the most appropriate antibiotic regimen for a 65-year-old man with acute bacterial sinusitis, presenting with purulent nasal discharge, facial pain, and a diminished sense of taste, who has an allergy to peanuts?

Management of Acute Bacterial Sinusitis in a 65-Year-Old Man

Amoxicillin-clavulanate 2 g/125 mg twice daily for 5 days is the most appropriate antibiotic regimen for this patient with acute bacterial sinusitis.

Clinical Presentation Analysis

This 65-year-old man presents with classic symptoms of acute bacterial sinusitis:

• 2-week history of purulent nasal discharge
• Facial pain
• Diminished sense of taste
• Bilateral maxillary tenderness
• Pattern of initial improvement followed by worsening (double sickening)

The "double sickening" pattern (initial improvement followed by worsening) is particularly important as it strongly suggests bacterial infection rather than viral etiology 1.

Antibiotic Selection Rationale

First-line Therapy

Amoxicillin-clavulanate is recommended as first-line therapy for acute bacterial sinusitis by multiple guidelines 2, 1. The high-dose formulation (2 g/125 mg twice daily) is preferred because:

1. It provides better coverage against resistant Streptococcus pneumoniae strains 1
2. It achieves superior tissue concentrations in the sinuses compared to standard dosing 3
3. The patient shows signs of more severe disease with symptoms lasting over 2 weeks 1

Duration of Therapy

A 5-day course is sufficient for uncomplicated acute bacterial sinusitis:

• Multiple studies show equivalent efficacy between 5-day and 10-day regimens 4, 5
• Shorter courses reduce risk of adverse effects, improve compliance, and minimize antimicrobial resistance 4
• The European Position Paper on Rhinosinusitis supports shorter courses for uncomplicated cases 2

Alternative Options Analysis

Doxycycline

While doxycycline (option B) is an acceptable alternative for patients with penicillin allergy 1, it is not the first-line choice when amoxicillin-clavulanate can be used. This patient has no documented penicillin allergy (only peanut allergy).

Fluoroquinolones (Levofloxacin/Moxifloxacin)

Fluoroquinolones (options C and D) should be reserved for:

• Patients with true penicillin allergy
• Treatment failures with first-line agents
• Complicated cases with risk of complications

The FDA label for levofloxacin confirms its indication for acute bacterial sinusitis 6, but guidelines recommend reserving fluoroquinolones as second-line agents due to:

• Risk of serious adverse effects
• Need to preserve these agents for more severe infections
• Equivalent efficacy of first-line agents for uncomplicated sinusitis

Important Clinical Considerations

Monitoring Response

• Assess for clinical improvement within 72 hours of starting antibiotics 1
• Consider switching to a broader-spectrum antibiotic if no improvement is seen

Adjunctive Treatments

• Intranasal corticosteroids to reduce inflammation
• Saline nasal irrigation to clear mucus and reduce inflammation
• Short-term nasal decongestants (≤5 days) may help relieve congestion

Red Flags for Complications

Be vigilant for signs of complications requiring immediate specialist referral:

• Orbital involvement (proptosis, visual changes, limited eye movement)
• Intracranial complications (altered mental status, severe headache)
• Persistent fever or worsening despite appropriate therapy

Conclusion

Based on the patient's presentation with classic symptoms of acute bacterial sinusitis including the "double sickening" pattern, amoxicillin-clavulanate 2 g/125 mg twice daily for 5 days provides optimal coverage against the most common pathogens while minimizing the risk of antimicrobial resistance and adverse effects.