What is the recommended treatment for bacterial sinusitis?

Treatment for 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

First-Line Antibiotic Selection

Amoxicillin-clavulanate is strongly preferred over amoxicillin alone due to the increasing prevalence of β-lactamase-producing Haemophilus influenzae (approximately 50% of strains) and Moraxella catarrhalis (90-100% of strains). 2, 1 This recommendation comes from both the American Academy of Pediatrics and the Infectious Diseases Society of America. 1

Dosing Recommendations

For adults:

• Standard dose: 875 mg/125 mg twice daily 1
• High-dose formulation: 2 g amoxicillin/125 mg clavulanate twice daily (maximum dose not to exceed 2 g every 12 hours) 2, 1

For 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 2, 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 2, 1

The high-dose regimen is designed to overcome penicillin resistance in Streptococcus pneumoniae, which affects 25-50% of strains. 2

Treatment Duration

Adults should receive 5-7 days of treatment for uncomplicated cases. 1, 3 A meta-analysis of 12 randomized controlled trials involving 4,430 patients demonstrated that short-course therapy (3-7 days) had equivalent clinical success compared to longer courses (6-10 days), with fewer adverse events in the 5-day regimen. 3

Children require 10-14 days of treatment. 2, 1 Some experts recommend continuing treatment until the patient is symptomatically improved to near normal, or for 7 days after becoming symptom-free. 2

Alternative Antibiotics for Penicillin-Allergic Patients

For non-severe penicillin allergy, second- or third-generation cephalosporins are safe alternatives, as the risk of cross-reactivity causing serious allergic reactions is negligible. 2, 1 Recommended options include:

• Cefuroxime: 250-500 mg twice daily (adults); 7.5 mg/kg twice daily (children) 2, 1
• Cefpodoxime: 200-400 mg twice daily (adults); 5 mg/kg twice daily (children) 2, 1
• Cefdinir: appropriate alternative with enhanced activity against β-lactamase-producing organisms 2, 1
• Cefprozil: 250-500 mg twice daily (adults); 15 mg/kg twice daily (children) 2, 1

For severe penicillin allergy, macrolides (clarithromycin 500 mg twice daily or azithromycin 250 mg daily) or quinolones may be considered, though these have weaker activity against S. pneumoniae. 2, 4

Fluoroquinolones (levofloxacin 500-750 mg daily, moxifloxacin, gemifloxacin) are effective alternatives in adults but should be reserved for patients with true penicillin allergy or treatment failure due to concerns about resistance and adverse effects. 2, 5, 6

Clinical Decision-Making Algorithm

When to Initiate Antibiotics

Prescribe antibiotics immediately for:

• Severe presentation: Temperature ≥39°C with purulent nasal discharge for ≥3 consecutive days 2
• Worsening presentation: Sudden worsening of respiratory symptoms after initial improvement 2
• Persistent presentation with complications: Orbital or intracranial complications, or coexisting acute otitis media, pneumonia, or streptococcal pharyngitis 2

Consider observation or antibiotics for:

• Persistent presentation without complications: Nasal symptoms or cough for >10 days without improvement 2 This presents an opportunity for shared decision-making with patients, as some will improve without antibiotics (number needed to treat: 3-5). 2

Do not prescribe antibiotics for:

• Symptoms lasting <7-10 days, as bacterial sinusitis is uncommon in this timeframe and most cases are viral. 2

Monitoring and Treatment Failure

Reassess patients at 72 hours if symptoms worsen or fail to improve. 2, 1 In randomized controlled trials, 51% of placebo-treated patients improved within 3 days, with minimal additional improvement between days 3-10, while 79% of antibiotic-treated patients improved by day 3. 2

Switch to alternative antibiotic if:

• No improvement after 3-5 days of initial therapy 2, 1
• Symptoms worsen within 48-72 hours 2, 1

For poor response to amoxicillin or in regions with high antibiotic resistance, appropriate second-line choices include high-dose amoxicillin-clavulanate, cefuroxime, cefpodoxime, or fluoroquinolones. 2

For sinusitis failing to improve after 21-28 days, consider broader-spectrum agents with or without anaerobic coverage (clindamycin 150-450 mg three to four times daily or metronidazole 250-500 mg three to four times daily). 2

Adjunctive Therapies

Intranasal corticosteroids are recommended as adjunctive treatment, particularly in patients with allergic rhinitis, to reduce inflammation and improve outcomes. 2, 1 These should be used in conjunction with antibiotics for recurrent acute and chronic sinusitis. 2

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

Supportive measures that may provide symptomatic relief include adequate rest, hydration, analgesics, warm facial packs, steamy showers, and sleeping with the head of the bed elevated. 2

Decongestants (topical and oral) are often used to decrease nasal resistance and theoretically increase ostial patency, though prospective studies demonstrating benefit are lacking. 2

Antihistamines have no proven role in acute bacterial sinusitis unless the underlying risk factor is allergic rhinitis. 2

Special Clinical Situations

For patients unable to tolerate oral medications, administer ceftriaxone 50 mg/kg IV or IM as a single dose, then transition to oral therapy once tolerated. 1

For severely ill or toxic-appearing patients, initiate inpatient IV therapy with cefotaxime or ceftriaxone and obtain otolaryngology consultation for possible sinus aspiration to obtain culture and susceptibility data. 2, 1

For recurrent sinusitis (≥3 episodes per year), evaluate for underlying inflammation, allergy, immunodeficiency, and anatomic abnormalities. 2 Consider sinus CT scan if not already performed. 2

When to Refer to Specialist

Refer to otolaryngologist, infectious disease specialist, or allergist-immunologist for:

• Immunocompromised patients 1
• Clinical deterioration despite extended antibiotic courses 1
• Recurrent sinusitis with clearing between episodes 2, 1
• Suspected complications (orbital or intracranial involvement) 1
• Chronic or recurrent sinusitis associated with otitis media, bronchitis, bronchiectasis, or pneumonia 2
• Evaluation of unusual pathogens, immunodeficiency, or structural abnormalities 2

Critical Pitfalls to Avoid

Do not routinely cover for MRSA during initial empiric therapy, as current data do not support this practice despite S. aureus being a potential pathogen. 1 Methicillin-susceptible S. aureus is covered by standard regimens. 2

Do not use plain amoxicillin as first-line therapy given the high prevalence of β-lactamase-producing organisms (50% of H. influenzae and 90-100% of M. catarrhalis). 2, 1

Do not prescribe antibiotics for viral rhinosinusitis. 2, 1 Ensure patients meet diagnostic criteria: symptoms >10 days without improvement, severe symptoms with high fever and purulent discharge for 3-4 days, or worsening after initial improvement. 2

Do not continue ineffective antibiotics beyond 3-5 days. 2, 1 Failure to reassess and switch therapy leads to prolonged illness and potential complications. 2, 1

Avoid first-generation cephalosporins (cephalexin, cefadroxil) and cefaclor, as they have poor coverage for H. influenzae and high rates of adverse reactions. 2

Avoid cefixime and ceftibuten, as they have poor activity against S. pneumoniae, especially penicillin-resistant strains, and should not be used for acute bacterial sinusitis. 2