Chronic rhino sinusitis (CRS) is a poorly understood inflammatory condition affecting the sinuses. It is characterized by waxing and waning symptoms, including nasal drainage or post nasal drip, changes in smell, nasal congestion, facial pressure or pain, ear fullness, cough, and fatigue. The clinical diagnosis of CRS is usually made based on the time course of the disease (symptoms present for more than three months) plus some combination of signs and symptoms, CT scan results, and an endoscopic nasal examination.