What is the recommended treatment for a patient with bacterial sinusitis?

Treatment of Bacterial Sinusitis

Amoxicillin-clavulanate is the preferred first-line antibiotic for acute bacterial sinusitis in both adults and children, with empiric therapy initiated as soon as the clinical diagnosis is established. 1

Confirming the Diagnosis Before Starting Antibiotics

Before prescribing antibiotics, confirm bacterial sinusitis using one of three clinical patterns 1:

• Persistent symptoms ≥10 days without improvement (nasal discharge, congestion, facial pain/pressure) 1
• Severe symptoms for ≥3 consecutive days (fever ≥39°C with purulent nasal discharge) 1
• "Double sickening" - worsening after initial improvement from a viral upper respiratory infection 1

Most acute rhinosinusitis (98-99.5%) is viral and resolves spontaneously within 7-10 days without antibiotics 2. Do not prescribe antibiotics for symptoms lasting <10 days unless severe symptoms are present 2.

First-Line Antibiotic Treatment

Adults

Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-7 days is the preferred first-line treatment 1, 2. The IDSA guideline explicitly recommends amoxicillin-clavulanate over amoxicillin alone due to coverage against β-lactamase-producing Haemophilus influenzae and Moraxella catarrhalis 1.

High-dose amoxicillin-clavulanate (2 g/250 mg twice daily) should be used for patients with 1, 2:

• Recent antibiotic use within the past 4-6 weeks
• Age >65 years
• Moderate-to-severe symptoms
• Comorbid conditions or immunocompromised state
• Geographic areas with high rates of penicillin-resistant Streptococcus pneumoniae

Children

High-dose amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate in 2 divided doses) is recommended as first-line therapy 1, 2. Children require the longer treatment duration of 10-14 days 1.

Standard-dose amoxicillin (45 mg/kg/day in 2 divided doses) may be used for uncomplicated cases without risk factors 2.

Treatment Duration

• Adults: 5-7 days for uncomplicated cases 1
• Children: 10-14 days 1
• Alternative guideline: Treat until symptom-free for 7 days (typically 10-14 days total) 2

When to Reassess and Switch Antibiotics

Reassess at 3-5 days (adults) or 72 hours (children) 1, 2:

If symptoms worsen or fail to improve, switch to second-line therapy 1:

• Respiratory fluoroquinolones (levofloxacin 500 mg once daily or moxifloxacin 400 mg once daily for 10 days) provide 90-92% predicted clinical efficacy 1, 2
• High-dose amoxicillin-clavulanate (if not already used) 2
• Third-generation cephalosporins (cefpodoxime, cefdinir) for superior H. influenzae coverage 2

Penicillin-Allergic Patients

Non-Type I Allergy (Rash, Mild Reactions)

Second- or third-generation cephalosporins are safe to use 2, 3:

• Cefuroxime-axetil 2, 3
• Cefpodoxime-proxetil 2, 3
• Cefdinir 2, 3

Recent evidence shows the risk of serious allergic reactions to second- and third-generation cephalosporins in penicillin-allergic patients is negligible 2, 3.

Type I Allergy (Anaphylaxis)

Respiratory fluoroquinolones are the first-line choice 2, 3:

• Levofloxacin 500 mg once daily for 10-14 days 2, 3
• Moxifloxacin 400 mg once daily for 10 days 2, 3

Doxycycline 100 mg once daily for 10 days is an acceptable alternative but has a predicted bacteriologic failure rate of 20-25% and limited activity against H. influenzae 2.

What NOT to Use

• Azithromycin and other macrolides should not be used as first-line therapy due to resistance rates exceeding 20-25% for both S. pneumoniae and H. influenzae 1, 2
• Trimethoprim-sulfamethoxazole has resistance rates of 50% for S. pneumoniae and 27% for H. influenzae 2
• First-generation cephalosporins (cephalexin, cefadroxil) have inadequate coverage against H. influenzae 2
• Routine coverage for MRSA is not recommended during initial empiric therapy 1

Essential Adjunctive Therapies

These improve outcomes regardless of antibiotic choice 1, 2:

• Intranasal corticosteroids (mometasone, fluticasone, or budesonide twice daily) reduce mucosal inflammation 1, 2
• Saline nasal irrigation (physiologic or hypertonic) provides symptomatic relief 1, 2
• Analgesics (acetaminophen, NSAIDs) for pain and fever 2
• Adequate hydration, warm facial packs, sleeping with head elevated 2

Do NOT use topical or oral decongestants/antihistamines as adjunctive treatment - they are not recommended 1.

When to Refer to a Specialist

Refer to otolaryngology when 1, 2:

• Symptoms refractory to two courses of appropriate antibiotics
• Recurrent sinusitis (≥3 episodes per year)
• Suspected complications (orbital cellulitis, meningitis, brain abscess)
• Immunocompromised patients who continue to deteriorate despite extended antimicrobial therapy
• Need for sinus aspiration/culture

Critical Pitfalls to Avoid

• Do not prescribe antibiotics for viral rhinosinusitis lasting <10 days unless severe symptoms are present 2
• Do not use fluoroquinolones as routine first-line therapy in patients without documented β-lactam allergies - reserve them to prevent resistance 2
• Do not continue ineffective therapy beyond 3-5 days (adults) or 72 hours (children) without reassessment 1, 2
• Complete the full antibiotic course even after symptoms improve to prevent relapse 2, 4
• Take amoxicillin-clavulanate with food to reduce gastrointestinal upset 4