Acute sinusitis is the inflammation of the sinuses as the result of an infection from a virus, bacteria or fungus. Chronic sinusitis, or chronic rhinosinusitis, is more severe than acute sinusitis. A patient is diagnosed with chronic rhinosinusitis when inflammation and swelling in the sinuses last for more than three months.
In addition to an infection, nasal polyps or a deviated septum can cause chronic sinusitis. Symptoms include drainage of a thick, yellow or greenish discharge from the nose or down the back of the throat, nasal obstruction or congestion, pain, tenderness and swelling around the eyes or reduced sense of smell and taste.