RESUMO
Acute rhinosinusitis is an important health problem. Even though its frequency is not well documented in our country?, the economic burden it bears is not insignificant as it notably alters the quality of life of affected patients. Its diagnosis is generally clinical in nature, with further studies reserved only for the differential diagnoses of complications or tumour-like processes. The most frequent causes are viral infections, although Streptococcus pneumoniae and Haemophilus influenzae are the most commonly isolated bacterial agents. Although complications are uncommon nowadays, they can be serious when they occur, and commonly include orbital infections, closely followed in frequency by intracranial and bone infections. Treatment should consist of symptomatic measures, like saline rinses and antibiotics in cases of bacterial origin.