Alternate Names : Sinus Infection
Sinusitis is an inflammation or infection of the linings of the sinuses and cavities of the nose. There are three major types of sinusitis:
acute sinusitis, which involves less than 3 weeks of symptoms
subacute sinusitis, with symptoms lasting 3 weeks to 3 months
chronic sinusitis, in which symptoms last longer than 3 months
What is going on in the body?
There are four pairs of sinuses which connect to the nose and throat. The sinuses are normally filled with air. They moisten, cleanse, and warm the air after it leaves the nose on the way to the lungs. The normal nose is a wonderful filter. It removes 80% of all tiny particles.
Acute allergic sinusitis occurs when the lining of the nose and sinuses becomes inflamed. Common causes include pollens, animal dander, and other allergens. These allergens set off an inflammatory response. Histamine and other chemicals are released, causing the symptoms of acute allergic sinusitis.
Viral sinusitis can occur together with an upper respiratory infection, or URI. Viruses attack the lining of the sinuses and cause swelling of the nasal tissues, which leads to symptoms.
Bacterial sinusitis can follow a viral infection if bacteria grow inside the sinuses. About 5 out of every 1,000 viral URIs are complicated by a bacterial sinus infection. Bacterial forms of sinusitis also occur when the drainage opening is blocked by swelling or narrowing. Then the normal bacteria in the sinus and nasal tracts overgrow and cause an infection.
Cold air sinusitis produces symptoms when the person is exposed to cold air. Aspirin sensitivity sinusitis may occur in some individuals when they take medicines containing aspirin.
What are the causes and risks of the condition?
Sinusitis may be caused by a virus, bacteria, allergen, or other factors as outlined above. People with immunodeficiency disorders are at higher risk for some types of sinusitis.