What is sinusitis? Author: admin Sinusitis is an inflammation or infection of the sinus cavities, which are located around the nasal passages. Usual symptoms include increased nasal secretions and pain or headache around the sinuses. Last modified:11-25-2009, 3:08 pm Number of views:976 Ketan C. Mehta, MD Diplomate, certified by American Boards of Internal Medicine, Pulmonary Medicine and Critical Care Medicine. Disclaimer