What is the treatment for sinusitis?

Treatment of Sinusitis

Distinguish Viral from Bacterial Sinusitis First

Most acute rhinosinusitis (98-99.5%) is viral and resolves spontaneously within 7-10 days without antibiotics—only prescribe antibiotics when acute bacterial sinusitis is confirmed by one of three specific clinical patterns. 1, 2

The three patterns that indicate bacterial sinusitis requiring antibiotics are:

• Persistent symptoms ≥10 days without clinical improvement 1, 2, 3
• Severe symptoms (fever ≥39°C with purulent nasal discharge and facial pain) for ≥3 consecutive days 1, 2
• "Double sickening" - worsening symptoms after initial improvement from a viral upper respiratory infection 1, 2

First-Line Antibiotic Treatment for Acute Bacterial Sinusitis

Amoxicillin remains the first-line antibiotic for uncomplicated acute bacterial sinusitis in both adults and children. 1, 2, 3

Adult Dosing

• Mild disease: 500 mg twice daily for 10-14 days 1, 3
• Moderate disease or high-resistance areas: 875 mg twice daily for 10-14 days 1, 3

Pediatric Dosing

• Standard therapy: 45 mg/kg/day in 2 divided doses 3
• High-dose therapy (for age <2 years, daycare attendance, recent antibiotic use, or high-resistance areas): 80-90 mg/kg/day in 2 divided doses 1, 3

The standard duration is 10-14 days or until symptom-free for 7 days. 4, 2, 3

When to Escalate to Second-Line Therapy

If no improvement occurs after 3-5 days of initial amoxicillin therapy, switch to amoxicillin-clavulanate (high-dose: 875 mg/125 mg twice daily for adults; 80-90 mg/kg/day amoxicillin component for children). 1, 2, 3

The addition of clavulanate provides coverage against β-lactamase-producing organisms (Haemophilus influenzae and Moraxella catarrhalis), which account for treatment failures. 4, 3

Penicillin-Allergic Patients

For patients with documented penicillin allergy, the treatment algorithm depends on allergy severity:

Non-Severe Allergy (Rash, Delayed Reactions)

Second- or third-generation cephalosporins are safe and effective first-line alternatives. 1, 2, 3

• Cefuroxime-axetil (second-generation) 2, 3
• Cefpodoxime-proxetil (third-generation, superior H. influenzae coverage) 2, 3
• Cefdinir (third-generation) 2, 3

The risk of cross-reactivity between penicillins and second/third-generation cephalosporins is negligible. 3

Severe Beta-Lactam Allergy (Anaphylaxis)

Respiratory fluoroquinolones should be reserved for severe penicillin allergy or treatment failures. 1, 3

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

These provide 90-92% predicted clinical efficacy against drug-resistant S. pneumoniae and β-lactamase-producing organisms. 3

Critical Pitfall: Avoid Azithromycin

Azithromycin should NOT be used for acute bacterial sinusitis due to resistance rates of 20-25% for both S. pneumoniae and H. influenzae. 3, 5 Despite FDA approval, multiple guidelines explicitly contraindicate macrolides as first-line therapy. 3

Adjunctive Therapies

Intranasal corticosteroids are strongly recommended as adjunctive therapy in both acute and chronic sinusitis to reduce inflammation and improve drainage. 1, 2, 3

Options include mometasone, fluticasone, or budesonide twice daily. 1

Additional supportive measures include:

• Analgesics (acetaminophen, NSAIDs) for pain relief 1, 2
• Saline nasal irrigation for symptomatic relief 1, 2
• Adequate hydration 1
• Warm facial packs 1
• Sleeping with head elevated 1

Short-term oral corticosteroids may be reasonable for patients with marked mucosal edema or failure to respond to initial treatment, typically for 5 days. 3

Chronic Sinusitis Management (Symptoms >8 Weeks)

Intranasal corticosteroids are first-line therapy for chronic sinusitis, combined with daily high-volume saline irrigation. 1, 2

For chronic infectious sinusitis, longer duration antibiotic therapy (minimum 3 weeks) may be required, with broader coverage against anaerobes and viridans streptococci. 4, 1, 2

Surgical intervention (functional endoscopic sinus surgery) should be considered for medically resistant sinusitis, with combined medical and surgical treatment achieving >60% cure rates after 3 years. 4, 2

When to Refer to a Specialist

Refer to an otolaryngologist or allergist/immunologist for: 1, 2

• Sinusitis refractory to two courses of appropriate antibiotics
• Recurrent sinusitis (≥3 episodes per year)
• Suspected complications (orbital or intracranial involvement)
• Need to clarify allergic or immunologic basis
• Symptoms lasting >8 weeks despite appropriate medical therapy

Critical Pitfalls to Avoid

Do not prescribe antibiotics for symptoms lasting <10 days unless severe symptoms are present (fever ≥39°C with purulent discharge for ≥3 consecutive days). 1, 2 The number needed to treat with antibiotics is 10-15, meaning most patients improve without them. 3

Never use first-generation cephalosporins (cephalexin) for sinusitis—they have inadequate coverage against H. influenzae, with nearly 50% of strains being β-lactamase producing. 3

Reserve fluoroquinolones appropriately to prevent resistance development—use only for treatment failures, severe disease, or documented severe beta-lactam allergy. 1, 3

Complete the full antibiotic course even after symptoms improve to prevent relapse. 2, 3