Sinusitis is inflammation of the sinuses. Germs such as bacteria, viruses, and fungi can cause an infection in the sinuses. Other conditions such as allergic rhinitis (swelling of the lining of the nose), small growths in the lining of the nose, or a shift in the nasal cavity can also cause sinusitis. This article deals with sinusitis caused by infections lasting less than two weeks. Sinus pressure, nasal congestion or discharge, loss of smell, and coughing are signs of a sinus infection. The nasal discharge may be white, yellow, green, or blood-tinged. Additionally, fever, dental pain, and bad breath may be present.