In a population of 100 children with suspected intracranial neurological disease, the overall prevalence of sinusitis signs on magnetic resonance images (MRI) is 45%. This figure exceeds the adult prevalence of 39%, while the nature of the lesions is more severe in children. Furthermore, paediatric sinuses seem to be affected according to a different pattern: adults have mainly maxillary and anterior ethmoidal lesions, whereas in children the sphenoidal and posterior ethmoidal sinuses are frequently involved too. Among children, the overall prevalence increases in the presence of a history of nasal obstruction (prevalence: 50%) and recent upper respiratory tract infection (prevalence: 81%) as well as when bilateral mucosal swelling (prevalence: 80%) or purulent secretions (prevalence: 100%) are seen on anterior rhinoscopy.