Acute rhinosinusitis
Inflammation of the nasal mucosa and paranasal sinuses that follows blockage of their narrow drainage pathways, almost always viral and self-limiting, with antibiotics reserved for the minority who develop true bacterial superinfection or complications.
Definition
Acute rhinosinusitis is inflammation of the nasal and paranasal sinus mucosa lasting less than 12 weeks, usually following a viral upper respiratory infection. Most cases are viral and self-limiting; only a minority have a bacterial cause.
First principles
The sinuses only stay healthy if their narrow drainage openings (ostia) stay open
The paranasal sinuses are air-filled cavities lined by ciliated mucosa that drain through small ostia into the nasal cavity. A viral upper-respiratory infection causes mucosal inflammation and oedema, narrowing these drainage pathways and impairing mucociliary clearance. The resulting congestion and retained secretions produce facial pressure, nasal blockage and discharge; this mechanism does not by itself imply bacterial infection.
This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.

