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What Causes the Symptoms of Sinusitis?

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.

  • The pain of a sinus attack arises because the trapped air and mucus put pressure on the mucous membrane of the sinuses and the bony wall behind it. Also, when a swollen membrane at the opening of a paranasal sinus prevents air from entering into the sinuses, it can create a vacuum that causes pain.
  • Mucus thickens because it loses its water content as it stays trapped inside the sinuses for a long time. In addition, inflammation leads to extra materials being secreted into the mucus, causing thickening.

Last Updated April 03, 2012