What are the treatment guidelines for acute sinus infection?

Treatment Guidelines for Acute Sinusitis

First-Line Antibiotic Therapy

Amoxicillin remains the first-line antibiotic for uncomplicated acute bacterial sinusitis in both adults and children, with treatment initiated only when specific clinical criteria are met. 1

When to Start Antibiotics

Antibiotic therapy is indicated when patients present with one of three distinct clinical patterns 1:

• Persistent symptoms: Nasal discharge or cough lasting ≥10 days without improvement 1
• Severe onset: Fever ≥39°C (102.2°F) with purulent nasal discharge for ≥3 consecutive days 1
• Worsening symptoms: Initial improvement followed by clinical deterioration 1

Physical examination findings supporting bacterial infection include purulent nasal discharge (often unilateral), sinus tenderness on palpation, and nasal congestion 1. Antibiotic therapy is definitely indicated for frontal, ethmoidal, or sphenoidal sinusitis due to higher complication risk 2, 3.

Dosing Regimens

Standard dose amoxicillin (500 mg twice daily in adults) is appropriate for mild disease without recent antibiotic exposure 1. High-dose amoxicillin (875 mg twice daily in adults; 90 mg/kg/day in children) should be used in areas with high prevalence of resistant Streptococcus pneumoniae or for moderate disease 1.

Treatment duration is typically 10-14 days, though some newer agents have demonstrated efficacy with 5-day courses 2, 3. The American Academy of Family Physicians recommends treating for 7 days after symptom resolution, with a minimum of 10 days total 4.

Penicillin-Allergic Patients

For non-anaphylactic penicillin allergy, second- or third-generation cephalosporins are safe alternatives 1:

• Cefuroxime-axetil 2, 1
• Cefpodoxime-proxetil 2, 1
• Cefdinir 1

Avoid cefixime and ceftibuten as they have poor activity against penicillin-resistant S. pneumoniae 1.

For severe penicillin allergy (anaphylaxis), respiratory fluoroquinolones (levofloxacin, moxifloxacin) are recommended 2, 4. However, fluoroquinolones should be reserved for treatment failures or complicated sinusitis (frontal, ethmoidal, sphenoidal) rather than first-line therapy 2.

Pristinamycin is another alternative for beta-lactam allergy 2.

Treatment Failure Management

Reassess patients who show no improvement within 72 hours (pediatrics) or 3-5 days (adults) of initiating therapy 2, 1. This is a critical decision point to prevent complications.

For treatment failure, switch to 2, 1:

• High-dose amoxicillin-clavulanate (90 mg/kg amoxicillin and 6.4 mg/kg clavulanate in children; up to 2g every 12 hours in adults) 3
• Respiratory fluoroquinolones (levofloxacin 750 mg daily or moxifloxacin) 2, 5
• Second-generation cephalosporins 1

After switching antibiotics, obtain cultures by direct sinus aspiration (not nasopharyngeal swab) if the patient continues to fail therapy 2. Endoscopically-guided middle meatus cultures are acceptable alternatives in adults 2.

Adjunctive Therapies

Intranasal corticosteroids are recommended as adjunctive therapy, particularly in patients with allergic rhinitis or significant mucosal inflammation 2, 1, 3. They reduce inflammation and promote drainage by decreasing edema around sinus ostia 4.

Short-term oral corticosteroids may be reasonable when patients fail initial treatment, demonstrate nasal polyposis, or have marked mucosal edema 1, 3.

Saline nasal irrigation can improve mucociliary clearance 4, 3.

Topical decongestants (oxymetazoline) may help reduce congestion but must be limited to ≤5 days to avoid rebound congestion (rhinitis medicamentosa) 3. Oral decongestants and antihistamines are NOT recommended as adjunctive treatment 2.

Special Situations

Complicated Sinusitis

Clinical signs requiring immediate hospitalization and parenteral antibiotics include 2:

• Meningeal signs
• Exophthalmos or palpebral edema
• Ocular mobility disorders
• Severe pain preventing sleep

Contrast-enhanced CT (axial and coronal views) is the imaging modality of choice for suspected suppurative complications, not MRI 2.

Sinusitis of Dental Origin

Antibiotic therapy is definitely indicated for unilateral maxillary sinusitis associated with upper unilateral dental infection 2, 3.

Watchful Waiting

Watchful waiting without immediate antibiotics is appropriate for adults with uncomplicated acute bacterial sinusitis when reliable follow-up can be assured 1. This approach is NOT recommended for severe presentations or high-risk patients.

Common Pitfalls to Avoid

• Overdiagnosis in viral infections: Most acute sinusitis cases are viral and resolve without antibiotics 3. Symptoms <7 days are unlikely to be bacterial 6.
• Inadequate treatment duration: Complete the full antibiotic course even after symptoms improve to prevent relapse 1.
• Overuse of fluoroquinolones: Reserve these for treatment failures or complicated cases, not uncomplicated first-line therapy 2, 3.
• Extended decongestant use: Limit topical decongestants to 5 days maximum 3.
• Nasopharyngeal cultures: These are unreliable and not recommended for microbiologic diagnosis 2.

Microbiology

The predominant bacterial pathogens are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis 1. Beta-lactamase production occurs in up to 20% of H. influenzae strains and 50-70% of M. catarrhalis strains, supporting the use of beta-lactamase stable agents in treatment failures 1.