What's Sinusitis?

Sinusitis

Say: syne-yuh-SYE-tis

Sinusitis is an infection of the sinuses, which are air-filled spaces in the bones of your face around the nose. Like the inside of your nose, the sinuses are lined with a thin layer of tissue called the mucous membrane that makes mucus (snot).

When you have a cold or allergies, the tiny holes that drain the sinuses can get blocked and trap mucus and germs in the sinuses, which can lead to sinusitis.