What is the recommended treatment for acute sinusitis?

Treatment of Acute Sinusitis

Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-7 days is the preferred first-line antibiotic for acute bacterial sinusitis in adults, with intranasal corticosteroids added as adjunctive therapy. 1, 2

Confirming the Diagnosis Before Treatment

Antibiotics should only be initiated when acute bacterial sinusitis is confirmed by one of three clinical patterns 1, 3:

• Persistent symptoms ≥10 days without clinical improvement (nasal discharge, congestion, facial pain/pressure, or cough)
• Severe symptoms for ≥3-4 consecutive days (high fever >39°C with purulent nasal discharge and facial pain)
• "Double sickening" - worsening symptoms after initial improvement from a viral upper respiratory infection

Most acute rhinosinusitis cases are viral and resolve without antibiotics within 7 days 3. Do not prescribe antibiotics for viral rhinosinusitis, as this leads to unnecessary adverse effects and promotes resistance 1.

First-Line Antibiotic Treatment

Adults

Amoxicillin-clavulanate is superior to plain amoxicillin due to 20-30% prevalence of β-lactamase-producing Haemophilus influenzae and 12-28% prevalence of β-lactamase-producing Moraxella catarrhalis 1:

• Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-7 days 1, 2
• Plain amoxicillin is rendered ineffective by β-lactamase-producing organisms and should not be used as first-line therapy 1

Children

• High-dose amoxicillin-clavulanate 80-90 mg/kg/day (of amoxicillin component) with 6.4 mg/kg/day clavulanate in 2 divided doses for 10-14 days 1, 3, 2
• This dosing is particularly important in areas with high prevalence of resistant S. pneumoniae or in children with risk factors (age <2 years, daycare attendance, recent antibiotic use) 3

Penicillin-Allergic Patients

Second- or third-generation cephalosporins are the preferred alternatives, as the risk of serious cross-reactivity is negligible 1, 3:

• Cefuroxime-axetil (second-generation) 1, 3
• Cefpodoxime-proxetil or cefdinir (third-generation) 1, 3
• Third-generation cephalosporins provide superior activity against H. influenzae compared to cefuroxime 3

Do not use azithromycin or clarithromycin due to 20-25% resistance rates in S. pneumoniae and H. influenzae 1, 3.

For severe beta-lactam allergy where cephalosporins are contraindicated, doxycycline 100 mg once daily for 10 days is acceptable but suboptimal, with predicted bacteriologic failure rates of 20-25% 3. Doxycycline is contraindicated in children <8 years due to tooth enamel discoloration 3.

Second-Line Treatment for Treatment Failure

If no improvement occurs within 3-5 days (adults) or 72 hours (children), switch to a respiratory fluoroquinolone 1, 3:

• Levofloxacin 500-750 mg once daily for 5-10 days 1, 4
• Moxifloxacin (alternative fluoroquinolone) 1, 3

Fluoroquinolones demonstrate 90-92% predicted clinical efficacy and 100% microbiologic eradication of S. pneumoniae, including multi-drug resistant strains (MDRSP) 1, 4. However, reserve fluoroquinolones for treatment failures, complicated sinusitis (frontal, ethmoidal, or sphenoidal), or multi-drug resistant organisms to prevent resistance development 1, 3, 2.

Treatment Duration

• Adults: 5-7 days until symptom-free for 7 days 1, 3, 2
• Children: 10-14 days 1, 3, 2
• Shorter 5-7 day courses in adults have comparable efficacy with fewer side effects 1, 3

Complete the full course of antibiotics even after symptoms improve to prevent relapse 3.

Adjunctive Therapies

Intranasal corticosteroids should be added to antibiotic therapy in all patients with acute bacterial sinusitis, particularly those with allergic rhinitis, to reduce inflammation and improve outcomes 1, 3, 2.

Additional supportive measures 1, 3:

• Intranasal saline irrigation
• Adequate hydration
• Analgesics (acetaminophen, NSAIDs) for pain
• Warm facial packs
• Sleeping with head elevated

Short-term oral corticosteroids (e.g., dexamethasone 4 mg) may be considered for acute hyperalgic sinusitis (severe pain) or marked mucosal edema when patients fail to respond to initial treatment, but should not be used as monotherapy 3.

Treatment Based on Anatomic Location

• Maxillary sinusitis (most common): Standard first-line antibiotics as above 1, 3
• Frontal, ethmoidal, or sphenoidal sinusitis: Consider fluoroquinolones (levofloxacin or moxifloxacin) due to potential for serious complications 1, 3

Critical Pitfalls to Avoid

• 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 (symptoms >10 days, severe symptoms for 3-4 days, or worsening after initial improvement) 1, 3
• Do not continue ineffective antibiotics beyond 3-5 days—failure to reassess and switch therapy leads to prolonged illness and potential complications 1, 3
• Do not use azithromycin or clarithromycin due to significant resistance patterns 1, 3
• Do not routinely cover for MRSA during initial empiric therapy, as current data do not support this practice 2
• Do not use fluoroquinolones as routine first-line therapy—reserve for treatment failures or complicated cases to prevent resistance 1, 3, 2
• Ensure adequate treatment duration (minimum 5 days in adults, 10-14 days in children) to prevent relapse 1, 3

Watchful Waiting Option

For adults with uncomplicated acute bacterial sinusitis, watchful waiting without antibiotics is an appropriate initial strategy when follow-up can be assured, with antibiotics started if no improvement by 7 days or worsening at any time 3. The number needed to treat with antibiotics is 3-5 for persistent symptoms 3.