Sinusitis - Chronic

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Overview, Causes, & Risk Factors

The sinuses are openings in the bones around the nose. There are 4 pairs of sinuses connected to the nasal cavity by small openings. Normally, air passes in and out of the sinuses, and mucus and fluid drain from the sinuses into the nose.

Sinusitis occurs when there is infection or inflammation due to allergies in one or more of the sinuses. Acute sinusitis is often associated with upper respiratory infections, as inflammation of the nasal passages prevents drainage of fluid from the sinuses, which allows infection of the sinuses to occur.

A deviated nasal septum or other obstruction of the nose may also trap fluid in a sinus, causing chronic sinusitis. Dental infections such as tooth abscess may spread into the sinus and infect it directly.

Chronic sinusitis is much less common than acute sinusitis. When sinusitis recurs frequently, or lasts for a prolonged period of time, it is classified as chronic. While acute sinusitis is usually caused by infection with a single type of bacteria or virus, chronic sinusitis is usually caused either by allergies or by infection with a mixture of different types of bacteria. Chronic sinusitis may have less severe symptoms than acute sinusitis but can cause damage and destruction to the tissues of the sinuses. It may flare up spontaneously or may follow respiratory infections such as colds.

Allergy to the aspergillus species of fungus appears to cause a particularly difficult to treat form of chronic sinusitis.