One clue is a frequent need for antibiotics. If you have been on antibiotics four or more times during the past year, there is an increased likelihood that you may have chronic sinusitis. That likelihood is even greater if the antibiotics were appropriately prescribed for bacterial sinusitis, not simply colds, and if you had at least temporary improvement while on antibiotics. Admittedly, not all patients have this recurring sinus infection pattern. Some patients simply have continuous nasal congestion with some discolored postnasal drainage, perhaps a poor sense of smell, and possibly fatigue that's reminiscent to sinusitis. Since it is difficult to make a diagnosis based simply on symptoms, a complete exam of your nasal cavity is important. Nasal endoscopes, which we have available in our office, are especially helpful. They allow us to see the type of secretions coming from the sinuses and detect problems inside the nasal cavity. Another key diagnosis component is a CT scan, also known as a CAT scan. We usually obtain the scan after a prolonged course of medical therapy or at your baseline (ie. on a typical day); however, sometimes we decide to obtain it during a flare-up. This x-ray study determines if there is swelling blocking the opening between the sinuses and the nasal cavity.