Risk Factors:

Sinusitis is one of the most common diseases in the United States, affecting about 1 in 7 adults each year. About 31 million Americans are diagnosed with sinusitis each year.

Young Children and Sinusitis

Before the immune system matures, all infants are susceptible to respiratory infections, with a possible frequency of one cold every 1 - 2 months. Young children are prone to colds and may have 8 - 12 bouts every year. Smaller nasal and sinus passages also make children more vulnerable to upper respiratory tract infections than older children and adults. Ear infections such as otitis media are also associated with sinusitis. Nevertheless, true sinusitis is very rare in children under 9 years of age. Some doctors believe it is greatly overdiagnosed in this population.

The Elderly and Sinusitis

The elderly are at specific risk for sinusitis. Their nasal passages tend to dry out with age. In addition, the cartilage supporting the nasal passages weakens, causing airflow changes. They also have diminished cough and gag reflexes and faltering immune systems and are at greater risk for serious respiratory infections than are young and middle-aged adults.

People with Asthma or Allergies

People with asthma or allergies are at higher risk for non-infectious inflammation in the sinuses. The risk for sinusitis is higher in patients with severe asthma. People with a combination of polyps in the nose, asthma, and sensitivity to aspirin (called Samter's, or ASA, triad) are at very high risk for chronic or recurrent acute sinusitis.

Hospitalization

Some hospitalized patients are at higher risk for sinusitis, particularly those with:

• Head injuries
• Conditions requiring insertion of tubes through the nose
• Breathing aided by mechanical ventilators. (Such patients may have a significantly higher risk for maxillary sinusitis.)
• Patients who had a weakened immune system (immunocompromised)

Other Medical Conditions Affecting the Sinuses

A number of medical conditions put people at risk for chronic sinusitis. They include:

• Diabetes
• Gastroesophageal reflux disease
• Nasal polyps or septal deviation
• AIDS and other disorders of the immune system predispose the patient to sinusitis (fungal infections are especially risky)
• Oral or intravenous steroid treatment
• Hypothyroidism -- causes congestion that clears up when the condition is treated
• Cystic fibrosis -- a genetic disorder in which the mucus is very thick and builds up
• Kartagener's syndrome

Miscellaneous Risk Factors

Dental Problems. Anaerobic bacteria are associated with infections from dental problems or procedures, which precipitate about 10% of cases of maxillary sinusitis.

Changes in Atmospheric Pressure. People who experience changes in atmospheric pressure, such as while flying, climbing to high altitudes, or swimming, risk sinus blockage and therefore an increased chance of developing sinusitis. (Swimming increases the risk for sinusitis for other reasons, as well.)

Cigarette Smoke and Other Air Pollutants. Air pollution from industrial chemicals, cigarette smoke, or other pollutants can damage the cilia responsible for moving mucus through the sinuses. Whether air pollution is an important cause of sinusitis and, if so, which pollutants are critical factors, is still not clear. Cigarette smoke, for example, poses a small but increased risk for sinusitis in adults. Second-hand smoke does not appear to have any significant effect on adult sinuses, although it may pose a risk for sinusitis in children.