Acute Sinusitis (Adult)

1. Clinical Overview

Summary

Acute rhinosinusitis (ARS) is inflammation of the paranasal sinuses and nasal cavity lasting less than 12 weeks, most commonly following a viral upper respiratory tract infection (URI). [1,2] The condition represents a significant healthcare burden, with approximately 20 million cases occurring annually in the United States alone. [3] While the vast majority of cases are viral and self-limiting, acute bacterial rhinosinusitis (ABRS) develops in fewer than 2% of cases and may require antibiotic therapy. [4,5]

Distinguishing viral from bacterial ARS is clinically challenging but essential for appropriate antibiotic stewardship. The European Position Paper on Rhinosinusitis and Nasal Polyps (EPOS 2020) provides evidence-based criteria for diagnosis and management. [2]

Key Facts

Clinical Pearls

• 10-Day Rule: Persistent symptoms beyond 10 days without improvement suggest bacterial superinfection [4,9]
• Double-Worsening: Initial improvement followed by symptom deterioration is highly specific for ABRS [4]
• Antibiotic Stewardship: Sinusitis accounts for 21% of adult antibiotic prescriptions, yet antibiotics rarely needed [10]
• Imaging Overuse: Routine imaging not recommended for uncomplicated acute sinusitis [11]
• Red Flag Recognition: Periorbital swelling demands urgent assessment for orbital complications [7,8]

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2. Epidemiology

Prevalence and Incidence

Demographics

Risk Factors

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3. Aetiology and Pathophysiology

Pathogenic Mechanisms

Normal Sinus Physiology
         ↓
Triggering Event (Viral URTI, Allergy, Trauma)
         ↓
Mucosal Inflammation and Oedema
         ↓
Sinus Ostial Obstruction
         ↓
Impaired Ventilation + Retained Secretions
         ↓
Reduced Oxygen Tension + Mucus Stasis
         ↓
VIRAL ACUTE RHINOSINUSITIS (90-98%)
         ↓ (minority, if prolonged obstruction)
Bacterial Colonization → Proliferation
         ↓
ACUTE BACTERIAL RHINOSINUSITIS (0.5-2%)
         ↓ (if untreated/severe)
Complications (Orbital, Intracranial)

Exam Detail: ### Molecular and Cellular Mechanisms

Mucociliary Clearance Disruption

• Normal ciliary beat frequency: 12-15 Hz at 37°C
• Viral infection reduces frequency by 30-50% [1]
• Mucus viscosity increases 2-3 fold during inflammation
• Ciliary denudation occurs with severe viral infection

Inflammatory Cascade

• Viral attachment triggers TLR3/7/8 activation
• Release of IL-1β, IL-6, IL-8, TNF-α
• Neutrophil recruitment and degranulation
• Epithelial barrier breakdown
• Goblet cell hyperplasia and mucus hypersecretion [2]

Ostiomeatal Complex (OMC) Anatomy

• Middle meatus: common drainage pathway for frontal, maxillary, anterior ethmoid sinuses
• Ethmoid infundibulum: narrowest point (2-3 mm)
• Minor oedema (1-2 mm) sufficient to obstruct drainage [11]

Bacterial Pathogenesis (ABRS)

• Biofilm formation in 70% of chronic/recurrent cases [17]
• Bacterial adhesins bind to damaged epithelium
• Proteases and toxins cause mucosal damage
• Immune evasion through capsular polysaccharides (S. pneumoniae)
• β-lactamase production (H. influenzae, M. catarrhalis) [6]

Microbiology

Viral Pathogens (90-98% of ARS)

Bacterial Pathogens (0.5-2% of ARS)

Fungal Pathogens (Rare, Immunocompromised)

• Aspergillus species (most common)
• Mucor species (rhinocerebral mucormycosis in diabetics) [15]
• Candida species

Sinus Anatomy and Drainage

Clinical Significance: Maxillary and anterior ethmoid sinuses account for 80-90% of acute sinusitis cases due to shared drainage via the middle meatus. [11]

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4. Clinical Presentation

Cardinal Symptoms (Diagnostic Criteria)

EPOS 2020 Diagnostic Criteria for ARS: [2]

• Symptom duration less than 12 weeks

• PLUS ≥2 of the following symptoms:

  1. Nasal blockage/congestion/obstruction
  2. Nasal discharge (anterior or posterior)
  3. Facial pain/pressure
  4. Reduction or loss of smell (hyposmia/anosmia)

• With at least one of: nasal blockage OR nasal discharge (must be present)

Symptom Profile

Features Suggesting Bacterial ARS (ABRS)

IDSA 2012 Criteria for Diagnosis of ABRS: [4]

1. Persistent symptoms (≥10 days) without improvement
   • OR
2. Severe symptoms at onset (≥3-4 days):
   • High fever (≥39°C/102.2°F)
   • AND purulent nasal discharge
   • AND facial pain
   • OR
3. Worsening symptoms ("double-sickening"):
   • Initial improvement
   • Followed by worsening after 5-7 days

Exam Detail: ### Natural History of Viral ARS

Gwaltney's Classic Study on Viral URI/Sinusitis: [1]

Critical Point: Persistence of symptoms beyond 10 days, even without fever, warrants consideration of ABRS as spontaneous resolution expected by this time. [4,9]

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5. Clinical Examination

General Inspection

Anterior Rhinoscopy (Nasal Speculum Examination)

Facial Palpation and Percussion

Note: Sensitivity and specificity of tenderness are low (50-70%) and do not reliably distinguish bacterial from viral ARS. [11]

Transillumination

• Technique: Darken room, place light source against cheek/supraorbital ridge
• Finding: Reduced translumination suggests fluid/thickening
• Clinical Value: Poor sensitivity (60%) and specificity (55%); not recommended in modern practice [11]

Red Flag Signs Requiring Urgent Assessment

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6. Differential Diagnosis

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7. Investigations

General Approach

EPOS 2020/IDSA 2012 Recommendations: [2,4]

• Uncomplicated ARS: Diagnosis is clinical; imaging and microbiology not recommended
• Rationale:
  • CT abnormalities present in 87% of viral URI patients (false positives) [11]
  • Sinus aspiration impractical and invasive
  • Overinvestigation drives unnecessary antibiotic use

When to Investigate

Imaging

Computed Tomography (CT) Paranasal Sinuses

Indications:

• Suspected orbital/intracranial complications [7]
• Recurrent or chronic rhinosinusitis [2,12]
• Pre-operative planning for endoscopic sinus surgery

Findings in ARS:

Limitations:

• Cannot distinguish viral from bacterial ARS [11]
• 40-87% asymptomatic patients with viral URI show CT abnormalities [11]
• Radiation exposure (~0.6-2 mSv)

Plain Sinus Radiographs

• Not recommended: Low sensitivity (76%), low specificity (79%); replaced by CT [11]

MRI Paranasal Sinuses

• Indications: Suspected intracranial complications, fungal sinusitis, malignancy [15,18]
• Advantages: Superior soft tissue detail, no radiation
• Limitations: More expensive, less readily available

Nasal Endoscopy

Indications:

• Recurrent ARS
• Failure of medical therapy
• Suspected anatomical abnormality, polyps, malignancy

Findings:

• Mucopurulent discharge from middle meatus (maxillary/frontal/anterior ethmoid)
• Polyps, anatomical variants
• Allows targeted sinus culture (if indicated)

Microbiology

Sinus Aspiration and Culture

• Gold Standard for bacterial diagnosis
• Indications (rare):
  • ICU/severely ill patients
  • Immunocompromised (identify unusual pathogens) [15]
  • Failure of multiple antibiotic courses
  • Suspected nosocomial sinusitis

Technique: Maxillary sinus puncture under LA (via inferior meatus or canine fossa)

Nasal Swab Culture

• NOT recommended: Poor correlation with sinus pathogens (50-60%) [4]
• Frequently contaminates with nasal flora

Other Investigations (Selected Cases)

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8. Management

General Principles

EPOS 2020/IDSA 2012 Key Messages: [2,4]

1. Most ARS is viral: Antibiotics not indicated
2. Symptomatic treatment is mainstay for viral ARS
3. Antibiotic stewardship is critical (sinusitis = 21% of adult antibiotic prescriptions) [10]
4. Criteria for antibiotics: Persistent (> 10 days), severe, or worsening symptoms [4]
5. Delayed prescribing strategy may reduce antibiotic use by 40% [9]

Symptomatic Management (All Patients)

Exam Detail: ### Evidence for Intranasal Corticosteroids

Cochrane Meta-Analysis (2016) – Mometasone for ARS:

• Symptom resolution: OR 2.5 (95% CI 1.8-3.5)
• Faster recovery by 3-5 days on average
• Number Needed to Treat (NNT): 8-10 for symptom resolution [9]

EPOS 2020: Recommends INCS for ARS with moderate-severe symptoms (> 7-8/10 VAS) or symptoms > 10 days. [2]

Antibiotic Therapy

Indications for Antibiotics (IDSA 2012) [4]

1. Persistent symptoms ≥10 days without improvement
2. Severe symptoms at onset (≥3-4 days):
   • High fever ≥39°C (102.2°F)
   • AND purulent nasal discharge
   • AND facial pain
3. Worsening symptoms (double-sickening):
   • Initial improvement followed by worsening after 5-7 days

First-Line Antibiotics (No Recent Antibiotic Use)

UK (NICE NG79 2017): [9]

USA (IDSA 2012): [4]

Exam Detail: ### Antibiotic Resistance Considerations

Current Resistance Patterns (USA/Europe): [6]

• S. pneumoniae:
  • "Penicillin-nonsusceptible: 15-25% (intermediate) + 10-15% (resistant)"
  • "Macrolide-resistant: 30-40%"
  • "Fluoroquinolone-resistant: less than 5%"
• H. influenzae:
  • β-lactamase production: 30-40%
  • "Ampicillin-resistant: 30-40%"
• M. catarrhalis:
  • β-lactamase production: > 95%

Rationale for Co-amoxiclav: β-lactamase inhibitor (clavulanic acid) overcomes resistance in H. influenzae and M. catarrhalis. [3,6]

Second-Line / Treatment Failure (≥72 hours)

Antibiotic Duration

• IDSA 2012: 5-7 days for adults (children 10-14 days) [4]
• NICE 2017: 5 days sufficient for uncomplicated ABRS [9]
• Rationale: Shorter courses reduce side effects and resistance without compromising efficacy [9]

Delayed (Backup) Antibiotic Prescribing

Strategy: Provide prescription but advise patient to:

• Use only if no improvement after 7-10 days
• OR symptoms worsen significantly
• OR develop red flag features

Evidence:

• Reduces immediate antibiotic use by 40% [9]
• Patient satisfaction remains high (> 80%)
• No increase in complications [9]

NICE NG79 Recommendation: Consider for patients with:

• Symptoms 7-10 days (not yet meeting "persistent" criteria)
• Mild-moderate symptoms
• Good understanding and safety-netting [9]

Surgical Management

Indications for ENT Referral

Functional Endoscopic Sinus Surgery (FESS)

Indications:

• Recurrent ARS with anatomical obstruction
• Chronic rhinosinusitis failing medical therapy [2,12]
• Complications requiring drainage (abscess)

Procedure:

• Widen natural sinus ostia
• Remove obstructive tissue (polyps, hypertrophic mucosa)
• Restore mucociliary clearance

Outcomes: 80-90% symptom improvement in appropriately selected patients [12]

Management Algorithm

Adult with Clinical Features of Acute Rhinosinusitis
                    ↓
      RED FLAGS present? (periorbital swelling, visual changes, meningism)
         ↓ YES                              ↓ NO
  EMERGENCY referral                 Assess severity and duration
  ENT/Ophthalmology                           ↓
  CT imaging                    ┌──────────────┴───────────────┐
                                ↓                              ↓
                        Duration less than 10 days              Duration ≥10 days
                        Mild-moderate                  OR severe at onset
                        symptoms                       OR double-worsening
                                ↓                              ↓
                        VIRAL ARS                      PROBABLE BACTERIAL ARS
                        (No antibiotics)               (Consider antibiotics)
                                ↓                              ↓
                        Symptomatic treatment:         1st-line antibiotic:
                        - Analgesia                    - Phenoxymethylpenicillin (UK)
                        - INCS (if mod-severe)         - Co-amoxiclav (USA, or severe)
                        - Saline irrigation            - Doxycycline (penicillin allergy)
                        - Short-term decongestant      Duration: 5 days
                                ↓                              ↓
                        Safety-netting:                PLUS symptomatic treatment
                        - Return if worse              ↓
                        - Return if no improvement     Review at 72 hours
                          after 10 days                ↓
                                ↓                      No improvement?
                        Consider delayed Rx            ↓
                                                       2nd-line antibiotic OR ENT referral

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9. Complications

Classification

Orbital Complications (Chandler Classification) [7]

Pathophysiology: Ethmoid sinusitis → spread via valveless veins or bone dehiscence → orbital involvement [7]

Microbiology: S. pneumoniae, H. influenzae, S. aureus, anaerobes [7]

Mortality: less than 1% with prompt treatment; up to 20-30% in cavernous sinus thrombosis [7,18]

Intracranial Complications [18]

Diagnosis: CT/MRI brain + sinuses, lumbar puncture (if safe), blood cultures [18]

Management: Emergency neurosurgery consultation; IV broad-spectrum antibiotics; surgical drainage if abscess [18]

Frontal Bone Osteomyelitis ("Pott's Puffy Tumour") [18]

• Clinical Features: Frontal swelling, doughy scalp mass over frontal bone
• Pathophysiology: Frontal sinusitis → osteomyelitis of anterior table
• Imaging: CT shows bone destruction, subperiosteal abscess
• Management: IV antibiotics (6-8 weeks) + surgical debridement

Mucocele

• Definition: Obstructed sinus → mucus accumulation → expansion
• Most Common: Frontal sinus (60%), ethmoid (30%)
• Presentation: Chronic, painless swelling; diplopia if orbital displacement
• Management: Surgical marsupialization

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10. Prognosis and Outcomes

Natural History

Prognostic Factors

Good Prognosis:

• Viral aetiology
• Short symptom duration (less than 7 days)
• Mild-moderate symptoms
• No comorbidities
• Appropriate treatment

Poor Prognosis (Prolonged Symptoms/Complications):

• Immunocompromised state [15]
• Anatomical obstruction (polyps, deviated septum)
• Antibiotic resistance [6]
• Delayed diagnosis of complications [7,18]
• Frontal/sphenoid sinusitis (proximity to orbit/brain)

Complications Impact

• Orbital cellulitis: Vision loss in less than 5% if promptly treated; up to 10-20% if delayed [7]
• Cavernous sinus thrombosis: Mortality 20-30% despite treatment; neurological sequelae in 30-50% survivors [18]
• Meningitis/brain abscess: Mortality 10-30%; seizures/neurodevelopmental delay in 10-30% survivors [18]

Chronic Sequelae

• Progression to chronic rhinosinusitis: 10-15% of recurrent ARS cases [2,12]
• Olfactory dysfunction: Persistent hyposmia/anosmia in 5-10% [2]
• Asthma exacerbation: United airway disease [13]

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11. Prevention

General Measures

Management of Allergic Rhinitis [13]

• Intranasal corticosteroids
• Oral antihistamines
• Allergen immunotherapy (if severe)
• Rationale: Controls mucosal inflammation, reduces ARS risk

Anatomical Correction

• Septoplasty: For significant septal deviation causing recurrent ARS [2]
• Polypectomy/FESS: For nasal polyps, recurrent ARS despite medical therapy [2,12]

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12. Evidence and Guidelines

Key Guidelines

Landmark Studies

1. Gwaltney et al. (1994): CT study showing 87% of viral URI patients have sinus abnormalities – imaging not discriminatory [11]
2. Rosenfeld et al. (2007): Placebo-controlled trial of amoxicillin for ARS – no benefit in unselected patients [9]
3. Chow et al. (2012): IDSA guideline consensus – defined clinical criteria for ABRS [4]
4. Fokkens et al. (2020): EPOS 2020 update – comprehensive rhinosinusitis management [2]
5. Fleming-Dutra et al. (2016): Antibiotic stewardship study – sinusitis accounts for 21% of adult antibiotic prescriptions (most inappropriate) [10]

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13. Examination Focus

Viva Questions and Model Answers

Q1: How would you differentiate viral from bacterial acute rhinosinusitis clinically?

Model Answer: "Distinguishing viral from bacterial ARS is challenging as both present with similar symptoms. I would use the IDSA 2012 criteria for bacterial ARS, which require one of three patterns:

1. Persistent symptoms for ≥10 days without improvement
2. Severe symptoms at onset (≥3-4 days) with high fever > 39°C, purulent discharge, and facial pain
3. Double-worsening: initial improvement followed by worsening after 5-7 days

The last pattern has the highest specificity (~96%). Importantly, purulent discharge alone is not discriminatory as it occurs in both viral and bacterial ARS. Viral ARS typically peaks at 3-5 days and resolves by 7-10 days.

If criteria for bacterial ARS are not met, I would manage as viral with symptomatic treatment only."

Q2: A 45-year-old woman with acute sinusitis develops periorbital swelling. What is your immediate management?

Model Answer: "Periorbital swelling is a red flag indicating potential orbital complication, which occurs in 60-75% of sinusitis complications. I would:

1. Immediate assessment:

   • Check visual acuity, pupillary reflexes, extraocular movements
   • Assess for proptosis, chemosis, relative afferent pupillary defect
   • Examine for other red flags (meningism, altered GCS)

2. Chandler classification to stage orbital involvement:

   • Stage I (preseptal): swelling, normal vision/movements
   • Stage II (orbital cellulitis): chemosis, painful eye movements
   • Stages III-V: proptosis, restricted movements, ↓ vision (abscess/cavernous sinus thrombosis)

3. Immediate actions:

   • Same-day ENT and ophthalmology referral
   • CT paranasal sinuses + orbits with contrast to define extent
   • Admit for IV broad-spectrum antibiotics (e.g., co-amoxiclav + metronidazole or ceftriaxone)
   • If abscess (Stages III-IV): emergency surgical drainage (FESS + abscess drainage)

4. Monitor: Visual acuity, eye movements, inflammatory markers

Delayed treatment of orbital abscess risks permanent vision loss and intracranial extension."

Q3: Discuss the role of antibiotics in acute sinusitis management.

Model Answer: "Antibiotics have a limited role in acute sinusitis due to:

1. Epidemiology: 90-98% of ARS is viral; only 0.5-2% develop bacterial superinfection
2. Natural history: Even bacterial ARS has 60-65% spontaneous resolution
3. Antibiotic stewardship: Sinusitis accounts for 21% of adult antibiotic prescriptions, yet most are inappropriate

Evidence:

• Rosenfeld (2007) placebo-controlled trial: amoxicillin showed no benefit in unselected ARS patients
• IDSA/NICE guidelines: restrict antibiotics to patients meeting specific criteria

Indications for antibiotics (IDSA 2012):

• Persistent symptoms ≥10 days without improvement
• Severe symptoms (high fever + purulent discharge + facial pain) at onset
• Double-worsening pattern

Recommended regimen (NICE 2017):

• 1st-line: Phenoxymethylpenicillin 500mg QDS x 5 days
• 2nd-line (severe/failure): Co-amoxiclav 500/125mg TDS x 5 days
• Penicillin allergy: Doxycycline 100mg OD/BD x 5 days

Delayed prescribing: Effective strategy reducing immediate antibiotic use by 40% without increasing complications.

Resistance concerns: S. pneumoniae penicillin-nonsusceptible (15-25%), H. influenzae β-lactamase (30-40%) – co-amoxiclav preferred for severe cases."

Q4: What are the complications of acute sinusitis and how do they arise?

Model Answer: "Complications of ARS are rare (less than 1% if treated) but potentially life-threatening. They classify into:

1. Orbital complications (60-75%):

• Mechanism: Ethmoid sinusitis spreads via valveless veins or bone dehiscence (lamina papyracea)
• Chandler classification: Preseptal cellulitis → Orbital cellulitis → Subperiosteal abscess → Orbital abscess → Cavernous sinus thrombosis
• Presentation: Periorbital swelling, pain, ↓ vision, restricted eye movements, proptosis
• Management: Urgent ENT/ophthalmology; IV antibiotics; surgical drainage if abscess

2. Intracranial complications (10-15%):

• Types: Meningitis, epidural/subdural abscess, brain abscess, cavernous sinus thrombosis
• Mechanism: Direct extension through posterior frontal/sphenoid sinus walls, or haematogenous spread
• Presentation: Severe headache, meningism, seizures, focal neurology, altered GCS
• Mortality: 10-30% (highest for subdural empyema, cavernous sinus thrombosis)
• Management: Emergency neurosurgery; IV antibiotics; surgical drainage

3. Osseous complications (5-10%):

• Pott's puffy tumour: Frontal bone osteomyelitis with subperiosteal abscess
• Presentation: Doughy frontal scalp swelling
• Management: IV antibiotics (6-8 weeks) + surgical debridement

Risk factors for complications:

• Frontal/sphenoid sinusitis (proximity to orbit/brain)
• Immunocompromise
• Delayed treatment
• Antibiotic resistance"

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14. Patient / Layperson Explanation

What is acute sinusitis? Acute sinusitis (also called rhinosinusitis) is inflammation and swelling of the air-filled spaces (sinuses) around your nose, cheeks, and forehead. It usually happens after a common cold when the virus causes the sinuses to become blocked and filled with mucus.

Is it serious? In most cases, acute sinusitis is not serious and gets better on its own within 1-2 weeks. It's caused by viruses (like the common cold) in over 90% of cases. Bacterial infection is rare (less than 2%) but may need antibiotics.

How do I know if I have sinusitis? You might have:

• Blocked or stuffy nose (on one or both sides)
• Yellow or green discharge from your nose or down the back of your throat
• Pain or pressure in your face, especially when bending forward (over your cheeks, forehead, or between your eyes)
• Reduced sense of smell
• Headache
• Sometimes a cough or fever

Do I need antibiotics? Probably not. Antibiotics only work for bacterial infections, but most sinus infections are caused by viruses (like colds). Antibiotics won't help viral sinusitis and may cause side effects like diarrhea or thrush.

You might need antibiotics if:

• Symptoms last more than 10 days without getting better
• You have severe symptoms from the start (high fever above 39°C, severe pain, and thick colored discharge)
• You improve at first, then get worse again after 5-7 days

Your doctor will decide if antibiotics are needed based on these criteria.

What can I do to feel better?

1. Painkillers: Paracetamol or ibuprofen for pain and fever
2. Steroid nasal spray: Mometasone or fluticasone (available over-the-counter) can reduce swelling and help you breathe – use for 2-3 weeks
3. Saltwater rinses: Wash out your nose with saline spray or a nasal douche 2-4 times daily
4. Decongestant spray: Xylometazoline can unblock your nose quickly, but only use for 5-7 days (longer use makes things worse)
5. Drink plenty of fluids and rest
6. Steam inhalation: Breathe steam from a bowl of hot water (not boiling) – may help loosen mucus

When should I see a doctor urgently? Go to A&E or call 999 if you develop:

• Swelling or redness around your eyes
• Changes in your vision (blurred, double vision, or loss of vision)
• Severe headache with a stiff neck or sensitivity to light
• Confusion or drowsiness

These could be signs of serious complications like infection spreading to your eye or brain.

How can I prevent sinusitis?

• Wash your hands frequently to avoid catching colds
• Stop smoking (smoking irritates your sinuses)
• Get your flu vaccine each year
• Manage allergies if you have hay fever (use antihistamines or nasal sprays)

When will I get better?

• Viral sinusitis: 70-80% of people improve within 7-10 days
• Bacterial sinusitis (with antibiotics): 90-95% improve within 5-7 days
• If you're not improving after 10 days, or getting worse, see your doctor

Summary: Most sinus infections are caused by viruses and get better on their own. Use painkillers, steroid nasal sprays, and saltwater rinses to feel better. Antibiotics are only needed if symptoms last > 10 days, are severe from the start, or you improve then worsen. Seek urgent help if you have swelling around your eyes, vision changes, or severe headaches.

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15. References

1. Gwaltney JM Jr, Phillips CD, Miller RD, Riker DK. Computed tomographic study of the common cold. N Engl J Med. 1994;330(1):25-30. doi:10.1056/NEJM199401063300105

2. Fokkens WJ, Lund VJ, Hopkins C, et al. European Position Paper on Rhinosinusitis and Nasal Polyps 2020. Rhinology. 2020;58(Suppl S29):1-464. doi:10.4193/Rhin20.600

3. Anon JB, Jacobs MR, Poole MD, et al. Antimicrobial treatment guidelines for acute bacterial rhinosinusitis. Otolaryngol Head Neck Surg. 2004;130(1 Suppl):1-45. doi:10.1016/j.otohns.2003.12.003

4. Chow AW, Benninger MS, Brook I, et al. IDSA clinical practice guideline for acute bacterial rhinosinusitis in children and adults. Clin Infect Dis. 2012;54(8):e72-e112. doi:10.1093/cid/cir1043

5. Jaume F, Valls-Mateus M, Mullol J. Common Cold and Acute Rhinosinusitis: Up-to-Date Management in 2020. Curr Allergy Asthma Rep. 2020;20(7):28. doi:10.1007/s11882-020-00917-5

6. Fleming-Dutra KE, Hersh AL, Shapiro DJ, et al. Prevalence of Inappropriate Antibiotic Prescriptions Among US Ambulatory Care Visits, 2010-2011. JAMA. 2016;315(17):1864-1873. doi:10.1001/jama.2016.4151

7. Yadalla D, Jayagayathri R, Padmanaban K, et al. Bacterial orbital cellulitis - A review. Indian J Ophthalmol. 2023;71(7):2687-2693. doi:10.4103/IJO.IJO_3283_22

8. Wong SJ, Levi J. Management of pediatric orbital cellulitis: A systematic review. Int J Pediatr Otorhinolaryngol. 2018;110:123-129. doi:10.1016/j.ijporl.2018.05.006

9. NICE. Sinusitis (acute): antimicrobial prescribing. NICE guideline [NG79]. October 2017. https://www.nice.org.uk/guidance/ng79

10. Vazquez Deida AA, Bizune DJ, Kim C, et al. Opportunities to Improve Antibiotic Prescribing for Adults With Acute Sinusitis, United States, 2016-2020. Open Forum Infect Dis. 2024;11(8):ofae420. doi:10.1093/ofid/ofae420

11. Rosenfeld RM, Piccirillo JF, Chandrasekhar SS, et al. Clinical practice guideline (update): adult sinusitis. Otolaryngol Head Neck Surg. 2015;152(2 Suppl):S1-S39. doi:10.1177/0194599815572097

12. Sedaghat AR. Chronic Rhinosinusitis. Am Fam Physician. 2017;96(8):500-506.

13. Arcimowicz M. Acute sinusitis in daily clinical practice. Otolaryngol Pol. 2021;75(4):40-50. doi:10.5604/01.3001.0015.2378

14. Arcimowicz M. Rational treatment of acute rhinosinusitis in the context of increasing antibiotic resistance. Otolaryngol Pol. 2024;78(6):1-11. doi:10.5604/01.3001.0054.7506

15. Preda MA, Sarafoleanu C, Mușat G, et al. Management of oculo-orbital complications of odontogenic sinusitis in adults. Rom J Ophthalmol. 2024;68(1):45-52. doi:10.22336/rjo.2024.09

16. Costan VV, Bogdănici CM, Gheorghe L, et al. Odontogenic orbital inflammation. Rom J Ophthalmol. 2020;64(2):116-121.

17. Butler FM, Hernandez DR. Acute Rhinosinusitis: Rapid Evidence Review. Am Fam Physician. 2025;111(1):47-53.

18. Carr TF. Complications of sinusitis. Am J Rhinol Allergy. 2016;30(4):241-245. doi:10.2500/ajra.2016.30.4322