What are the recommended treatments for bacterial sinusitis?

Treatment of Bacterial Sinusitis

Amoxicillin-clavulanate is the first-line antibiotic for acute bacterial sinusitis in both adults and children, with treatment duration of 5-7 days in adults and 10-14 days in children. 1

Confirming Bacterial Sinusitis Before Treatment

Before prescribing antibiotics, ensure the patient meets diagnostic criteria for bacterial (not viral) sinusitis 1:

• Persistent symptoms ≥10 days without improvement 1
• Severe symptoms (fever >39°C, purulent nasal discharge, facial pain) for ≥3-4 consecutive days 1
• "Double sickening" - worsening after initial improvement from viral URI 1

Most acute rhinosinusitis is viral and resolves without antibiotics within 7 days 1. Do not prescribe antibiotics for viral rhinosinusitis.

First-Line Antibiotic Selection

Adults

Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-7 days is strongly preferred over amoxicillin alone due to increasing prevalence of β-lactamase-producing Haemophilus influenzae and Moraxella catarrhalis 1.

For patients with recent antibiotic use, moderate-to-severe symptoms, age >65, diabetes, immunocompromised status, or high local prevalence of resistant S. pneumoniae, use high-dose amoxicillin-clavulanate (2 g amoxicillin/125 mg clavulanate twice daily) 1, 2.

Plain amoxicillin should not be used as first-line therapy given high prevalence of β-lactamase-producing organisms 1.

Children

• Standard dose: 45 mg/kg/day of amoxicillin component in 2 divided doses for mild-moderate disease in children ≥2 years without recent antibiotic exposure 1
• High dose: 80-90 mg/kg/day of amoxicillin component (maximum 2 g per dose) with 6.4 mg/kg/day clavulanate for children <2 years, those in daycare, or with recent antibiotic use 1
• Duration: 10-14 days 1

Penicillin-Allergic Patients

For non-severe penicillin allergy, second- or third-generation cephalosporins are safe and effective, as the risk of cross-reactivity causing serious allergic reactions is negligible 1:

• Cefuroxime 1
• Cefpodoxime 1
• Cefdinir 1
• Cefprozil 1

For severe beta-lactam allergy, use respiratory fluoroquinolones (levofloxacin 500-750 mg once daily or moxifloxacin 400 mg once daily for 5-10 days) 2. However, fluoroquinolones should be reserved for this specific indication to prevent resistance development 1, 2.

Do not use azithromycin or other macrolides as first-line therapy due to 20-25% resistance rates 1.

Doxycycline 100 mg once or twice daily for 10 days is an acceptable alternative but has limited activity against H. influenzae and a predicted bacteriologic failure rate of 20-25% 3.

Adjunctive Therapies

Intranasal Corticosteroids

Strongly recommended as adjunctive treatment, particularly in patients with allergic rhinitis, to reduce inflammation and improve outcomes 1.

Saline Irrigation

Intranasal saline irrigation (physiologic or hypertonic) is recommended in adults to improve mucociliary clearance and reduce nasal congestion 1.

Oral Corticosteroids

May be reasonable for short-term use (typically 5 days) when patients fail to respond to initial treatment or have marked mucosal edema 3. However, intranasal corticosteroids are preferred over systemic steroids due to better safety profiles 3.

Treatment Failure Protocol

Reassess patients at 72 hours if symptoms worsen or fail to improve 1.

If no improvement occurs after 3-5 days of initial therapy or symptoms worsen within 48-72 hours 1:

• Switch to high-dose amoxicillin-clavulanate (if not already used) 1, 3
• Consider respiratory fluoroquinolones (levofloxacin or moxifloxacin) 1, 2
• For patients unable to tolerate oral medications, administer ceftriaxone 50 mg/kg IV or IM as a single dose, then transition to oral therapy 1

After 7 days without improvement, reevaluate for misdiagnosis, complications, need for imaging or endoscopy, or sinus aspiration for culture 2.

Special Clinical Situations

Severely Ill or Toxic-Appearing Patients

Initiate inpatient IV therapy with cefotaxime or ceftriaxone and obtain otolaryngology consultation for possible sinus aspiration 1.

Frontal, Ethmoidal, or Sphenoidal Sinusitis

Consider fluoroquinolones active against pneumococci (levofloxacin, moxifloxacin) due to potential for serious complications 3.

When to Refer to Specialist

Refer to otolaryngologist, infectious disease specialist, or allergist for 1:

• Immunocompromised patients
• Clinical deterioration despite extended antibiotic courses
• Recurrent sinusitis (≥3 episodes per year) with clearing between episodes
• Suspected complications (orbital or intracranial involvement)

Critical Pitfalls to Avoid

• Do not routinely cover for MRSA during initial empiric therapy, as current data do not support this practice 1
• Do not use plain amoxicillin as first-line therapy given high prevalence of β-lactamase-producing organisms 1
• Do not prescribe antibiotics for viral rhinosinusitis—ensure patients meet diagnostic criteria 1
• Do not continue ineffective antibiotics beyond 3-5 days—failure to reassess and switch therapy leads to prolonged illness and potential complications 1
• Do not use fluoroquinolones as routine first-line therapy for uncomplicated cases to prevent promoting resistance 2
• Ensure adequate treatment duration (minimum 5 days in adults, typically 7-10 days; 10-14 days in children) to prevent relapse 1, 3