Sinusitis (acute rhinosinusitis).

Introduction Acute rhinosinusitis is defined pathologically by transient inflammation of the mucosal lining of the paranasal sinuses lasting less than 4 weeks. Clinically, it is characterised by nasal congestion, rhinorrhoea, facial pain, hyposmia, sneezing, and, if more severe, additional malaise and fever. It affects 1% to 5% of the adult population each year in Europe.