Cystic FibrosisNational Heart Lung and Blood Institute
Primary Immune Deficiency DiseaseNational Institute of Child Health & Human Development
The paranasal sinuses, like the inside of your nose, are lined with a thin layer of tissue called the mucous membrane, which produces mucus. This mucus flows out through openings of the paranasal sinuses and into the nose. When these openings become blocked, your sinuses are affected.
Anything that causes swelling in the nose can block the openings between your paranasal sinuses and your nose, including a cold, an allergic reaction such as hay fever, or a reaction to some chemical to which you've been exposed. The blockage causes air and mucus to become trapped within the sinuses. This may cause pain and thickened mucus.
Last Updated April 03, 2012