Acute bacterial rhinosinusitis is the mucosal inflammation of the nose and paranasal sinuses caused by bacteria lasting ≥10 days for up to 4 weeks with no clinical improvement, severe signs or symptoms [eg high fever (39°C), purulent nasal discharge, facial pain] of ≥3-4 consecutive days, and worsening of symptoms within 10 days after initial improvement.
It is often preceded by a viral upper respiratory tract infection, rhinitis or other conditions that impair local or systemic immune function (eg nonallergic rhinitis, dental infection, mechanical obstruction of the nose, cystic fibrosis, ciliary dysfunction, immunodeficiency that impair the sinus drainage).
Signs and symptoms are nonspecific and typically difficult to differentiate from viral upper respiratory tract infection.
There is fever with nasal obstruction/congestion or anterior and/or posterior purulent drainage, with or without facial pressure/pain/fullness and reduction/loss of smell. Streptococcus pneumoniae and unencapsulated strains of Haemophilus influenzae cause half of acute rhinosinusitis cases.