Sinusitis is a topic covered in the 5-Minute Clinical Consult.

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  • Acute sinusitis is a symptomatic inflammation of ≥1 paranasal sinuses of <4 weeks duration resulting from impaired drainage and retained secretions accompanied by obstruction, facial pain/pressure/fullness, or both. Because rhinitis and sinusitis usually coexist, “rhinosinusitis” is the preferred term.
  • Disease is subacute when symptomatic for 4 to 12 weeks, recurrent acute when ≥4 annual episodes without persistent symptoms in between, and chronic when symptomatic for >12 weeks.
  • Uncomplicated rhinosinusitis has no extension of inflammation beyond paranasal sinuses and nasal cavity.
  • System(s) affected: head/eyes/ears/nose/throat (HEENT), pulmonary


  • Affects 1 in 8 adults accounting for >30 million individuals in the United States each year diagnosed with rhinosinusitis
  • Diagnosis of acute bacterial rhinosinusitis remains the fifth leading reason for prescribing antibiotics.
  • 0.5–2% of viral rhinosinusitis episodes have a bacterial superinfection.
  • Viral cause in 90–98% of cases

Incidence is highest in early fall through early spring (related to incidence of viral upper respiratory infection [URI]). Adults have two to three viral URIs per year; 90% of these colds are accompanied by viral rhinosinusitis. It is the fifth most common diagnosis made during family physician visits.

Etiology and Pathophysiology

  • Important features
    • Inflammation and edema of the sinus mucosa
    • Obstruction of the sinus ostia
    • Impaired mucociliary clearance
  • Secretions that are not cleared become hospitable to bacterial growth.
  • Inflammatory response (neutrophil influx and release of cytokines) damages mucosal surfaces.
  • Viral: vast majority of cases (rhinovirus; influenza A and B; parainfluenza virus; respiratory syncytial, adeno-, corona-, and enteroviruses)
  • Bacterial (complicates 0.5–2% of viral cases)
    • More likely if symptoms worsen within 5 to 6 days after initial improvement
    • No improvement within 10 days of symptom onset
    • >3 to 4 days of fever >102°F and facial pain and purulent nasal discharge
    • Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis are the most common bacterial pathogens.
    • Often overdiagnosed, which leads to overuse of and increasing resistance to antibiotics
    • Methicillin-resistant Staphylococcus aureus present in 0–15.9% of patients
  • Fungal: seen in immunocompromised hosts (uncontrolled diabetes, neutropenia, use of corticosteroids) or as a nosocomial infection

No known genetic pattern

Risk Factors

  • Viral URI
  • Allergic rhinitis
  • Asthma
  • Cigarette smoking
  • Dental infections and procedures
  • Anatomic variations
    • Tonsillar and adenoid hypertrophy
    • Turbinate hypertrophy, nasal polyps
    • Cleft palate
  • Immunodeficiency (e.g., HIV)
  • Cystic fibrosis (CF)

General Prevention

  • Hand washing to prevent transmission of viral infection
  • Childhood vaccinations up to date
  • Avoid close contacts with symptomatic individuals.
  • Avoid smoking and exposure to secondhand smoke.

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