It is present when the tissue that lines the sinuses becomes swollen or inflamed and occurs because of an infection by viruses, fungi, or bacteria. The paranasal sinuses are air-filled spaces in the skull, located behind the forehead, the bones of the nose, the cheeks, and the eyes. Healthy sinuses do not contain bacteria or other microorganisms.

Treatment: You generally do not need any treatment other than symptomatic relief with pain relievers, decongestants, and saline nasal washes. Chronic sinusitis may require the use of antibiotics.