Rhinosinusitis - Acute, Bacterial Disease Background

Last updated: 12 January 2026
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Introduction

Acute rhinosinusitis (ARS) in adults is defined as mucosal inflammation of the nose and paranasal sinuses for <12 weeks, characterized by ≥2 of the following symptoms: Nasal blockage/obstruction/congestion or nasal discharge (anterior/posterior nasal drip) with or without facial pain/pressure or cough and reduced or loss of smell. Acute bacterial rhinosinusitis (ABRS) is defined as acute rhinosinusitis caused by bacteria and is diagnosed based on clinical presentation or the presence of bacteria in the paranasal sinus cavity.

Epidemiology

The prevalence of acute rhinosinusitis appears to be rising, and it is currently the fifth most common condition for which antibiotics are prescribed. Among adults presenting with sinusitis symptoms in general medicine clinics, up to 38% may have acute bacterial rhinosinusitis. In otolaryngology practices, the prevalence is higher, ranging from 50% to 80%. Rhinosinusitis is most common among adults aged 45-65 years old. The incidence of acute bacterial rhinosinusitis is higher in women than men.

 

Etiology

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Streptococcus pneumoniae and unencapsulated strains of Haemophilus influenzae cause approximately 75% of acute rhinosinusitis cases. Moraxella catarrhalis accounts for 2-10% of the cases and is more common among children. Approximately 3-7% of the cases may be due to Streptococcus pyogenes and anaerobic bacteria. Staphylococcus aureus and other Streptococcal sp may occasionally cause rhinosinusitis. Gram-negative bacilli are rarely recovered in cases of acute rhinosinusitis. Microaerophilic and anaerobic bacteria may be identified and isolated if the acute bacterial rhinosinusitis is due to the extension of dental root infection to the sinus cavity.

Pathophysiology

Acute bacterial rhinosinusitis commonly occurs as a complication of a viral infection (upper respiratory tract infection [URTI]), rhinitis, or other conditions that impair local or systemic immune function (eg non-allergic rhinitis, dental infection, mechanical obstruction of the nose, cystic fibrosis, ciliary dysfunction, immunodeficiency that impairs the sinus drainage).


Risk Factors

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The most common predisposing factor to acute bacterial rhinosinusitis (ABRS) is a viral upper respiratory tract infection (URTI). Other predisposing factors include: The presence of medical conditions (eg allergic rhinitis, vasomotor rhinitis, cystic fibrosis, immunodeficiency, Kartagener syndrome), irritants (eg environmental tobacco smoke, air pollution, chlorine), anatomic factors (eg deviated nasal septum, adenoidal hypertrophy, immotile cilia, polyps, tumors, foreign bodies, granulomatosis with polyangiitis), odontogenic sources, medications (eg overuse of topical decongestants, cocaine abuse), and trauma (eg dental procedures, diving).