http://www.entlink.net/healthinfo/sinus/sinusitis.cfm
American Academy of Otolaryngology--Head and Neck Surgery
This patient health sheet describes sinusitis, an infection of the sinus cavities caused by bacteria. It usually is preceded by a cold, allergy attack, or irritation by environmental pollutants. The fact sheet includes information on acute sinusitis becoming chronic, treating sinusitis, sinus surgery, children and sinusitis, and more.