Acute Bacterial Sinusitis Treatment Guide 2025: Symptoms, Causes & Relief
Discover expert 2025 insights on acute bacterial sinusitis—its causes, symptoms, diagnosis, and proven treatments for fast, lasting sinus relief.
Introduction: Understanding Acute Bacterial Sinusitis
Acute bacterial sinusitis (ABS), also called acute bacterial rhinosinusitis, is one of the most common reasons for antibiotic prescriptions in primary care. It occurs when bacteria infect the sinus cavities after a viral upper respiratory infection (like a cold), causing inflammation, mucus buildup, and pressure pain.
While most sinus infections are viral and resolve without antibiotics, bacterial sinusitis requires targeted treatment to prevent chronic complications such as persistent infection, abscesses, or orbital cellulitis.
This article provides an in-depth overview of causes, symptoms, diagnosis, and current treatment guidelines — helping you or your patients make informed, evidence-based decisions in 2025.
What Is Acute Bacterial Sinusitis?
Definition
Acute bacterial sinusitis is defined as:
“An acute infection of the paranasal sinuses lasting less than 4 weeks, caused by bacterial pathogens, and typically following a viral upper respiratory infection.”
It primarily affects the maxillary sinuses, but can involve frontal, ethmoid, or sphenoid sinuses.
Duration & Classification
Acute: < 4 weeks
Subacute: 4–12 weeks
Chronic: > 12 weeks
Anatomy Overview: How the Sinuses Work
The sinuses are air-filled cavities located around your nose and eyes:
Maxillary (cheeks)
Frontal (forehead)
Ethmoid (between the eyes)
Sphenoid (behind the eyes)
Each sinus is lined with mucosa that traps pathogens. Normally, mucus drains through small openings into the nasal passages. Inflammation from a cold or allergy can block drainage, creating a moist, oxygen-poor environment where bacteria thrive.
Causes of Acute Bacterial Sinusitis
Primary Causes
Post-viral infection (most common) – About 0.5–2% of viral sinus infections become bacterial.
Allergies (allergic rhinitis) – Chronic nasal inflammation predisposes to blockage.
Anatomical obstructions – Deviated septum, nasal polyps, or enlarged turbinates.
Dental infections – Upper molar infections can spread to maxillary sinuses.
Air pollution and smoking – Damage cilia that clear mucus.
Common Bacterial Pathogens
Streptococcus pneumoniae
Haemophilus influenzae
Moraxella catarrhalis (more common in children)
Less commonly: Staphylococcus aureus, anaerobes
Symptoms of Acute Bacterial Sinusitis
Typical Symptoms
Nasal congestion or obstruction
Purulent (yellow-green) nasal discharge
Facial pain or pressure (especially unilateral)
Headache that worsens when bending forward
Postnasal drip or sore throat
Fever (moderate to high)
Reduced or lost sense of smell
Distinguishing from Viral Sinusitis
Diagnosis of Acute Bacterial Sinusitis
Clinical Diagnosis
Diagnosis is usually clinical, based on:
Symptoms persisting ≥10 days without improvement
Severe symptoms (fever >39°C, purulent discharge, pain) for ≥3–4 consecutive days
"Double worsening" pattern — initial improvement followed by relapse
Physical Examination
Tenderness over sinuses (maxillary, frontal)
Swollen nasal mucosa
Mucopurulent nasal drainage
Imaging (if needed)
Imaging is not routinely required, but may be used when:
Complications are suspected
Recurrent or atypical infections
Poor response to treatment
CT scan of the sinuses is the gold standard for evaluating sinus anatomy and extent of infection.
Treatment of Acute Bacterial Sinusitis
1. Symptomatic Relief (for all patients)
Nasal saline irrigation – Helps thin mucus and promote drainage.
Steam inhalation – Reduces congestion naturally.
Intranasal corticosteroids – E.g., fluticasone or mometasone, reduce inflammation.
Pain relief – Paracetamol (acetaminophen) or ibuprofen for headache and fever.
Decongestants – Short-term use (≤3 days) of nasal sprays like oxymetazoline.
🩺 Note: Overuse of decongestant sprays can cause rebound congestion (rhinitis medicamentosa).
2. Antibiotic Therapy
Antibiotics are indicated if:
Symptoms persist >10 days
Severe symptoms (fever + purulent discharge + facial pain)
“Double worsening” pattern
First-Line Antibiotics (Adults)
Amoxicillin-clavulanate (Augmentin) 875 mg/125 mg PO twice daily for 5–7 days
Broader coverage for H. influenzae and M. catarrhalis
Alternatives (if allergic to penicillin):
Doxycycline 100 mg PO twice daily for 5–7 days
Levofloxacin or Moxifloxacin (reserved for resistant cases)
Children
Amoxicillin-clavulanate 45 mg/kg/day divided every 12 hours
Duration: 10–14 days
💊 Avoid azithromycin due to rising bacterial resistance.
3. Adjunctive Measures
Adequate hydration
Humidifier use in dry environments
Avoid smoking and exposure to pollutants
Manage allergies with antihistamines or nasal steroids
Elevate head during sleep to improve drainage
Complications (If Untreated)
While rare, untreated bacterial sinusitis can spread to adjacent areas:
Orbital cellulitis or abscess (eye swelling, pain)
Osteomyelitis of the frontal bone
Meningitis or brain abscess
Chronic sinusitis (>12 weeks)
Immediate medical attention is required if you notice:
Vision changes or double vision
Severe headache or confusion
High fever with swelling around the eyes
Prevention Strategies
Healthy Habits
Wash hands frequently during cold season
Manage allergies proactively
Avoid cigarette smoke and pollutants
Use saline nasal spray daily during dry weather
Stay hydrated and maintain good nasal hygiene
Vaccinations
Pneumococcal vaccine and influenza vaccine reduce the risk of bacterial sinus infections triggered by viral illness.
FAQs: Acute Bacterial Sinusitis
Q1: How long does bacterial sinusitis last?
Typically 7–14 days, but recovery may take longer with severe or recurrent infections.
Q2: Can I treat sinusitis without antibiotics?
Yes — most sinus infections are viral. Supportive care like saline rinses, hydration, and rest often help. Antibiotics are only needed for confirmed bacterial cases.
Q3: What’s the difference between bacterial and viral sinusitis?
Viral improves within 7–10 days; bacterial lasts longer or worsens after initial improvement.
Q4: Can sinusitis spread to the brain or eyes?
Rarely, but untreated bacterial infections can spread to nearby structures, causing serious complications.
Q5: Is sinusitis contagious?
The infection itself isn’t, but the viral illness that precedes it can be.
Q6: When should I see a doctor?
If you have severe pain, fever, swelling around eyes, or symptoms lasting more than 10 days.
Conclusion
Acute bacterial sinusitis is a common but often overtreated condition. Understanding the distinction between viral and bacterial forms helps prevent unnecessary antibiotic use.
With proper diagnosis, targeted therapy, and preventive care, most cases resolve quickly and fully. If symptoms persist, worsen, or recur, consult an ENT specialist to rule out chronic sinusitis or structural causes.
For more evidence-based guidelines, visit the CDC Sinus Infection Resource and IDSA Clinical Practice Guidelines.
