Sinusitis is a common but frequently underdiagnosed and undertreated c
ondition. Because of its subtle presentation, the diagnostic index of
suspicion for chronic sinusitis must be high. The use of CT scans has
helped considerably in diagnosis. Functional endoscopic sinus surgery
is the treatment of choice in medically resistant cases. The associati
on of sinusitis and asthma emphasizes the relationship between the upp
er and lower airways.