Sinusitis
Causes, incidence, and risk factors:
The sinuses are air-filled spaces in the skull (behind the forehead, nasal bones, cheeks, and eyes) that are lined with mucus membranes. Healthy sinuses contain no bacteria or other organisms (they are sterile) and are open, allowing mucus to drain and air to circulate.
When inflamed, the sinuses become blocked with mucus and can become infected. Each year, over 30 million adults and children get sinusitis.
Sinusitis can be acute (lasting anywhere from 2 - 8 weeks) or chronic, with symptoms lingering much longer.
Sinusitis can occur from one of these conditions:
- Small hairs (cilia) in the sinuses, which help move mucus out, are not working properly.
The small openings (ostia) from the sinuses to the nose become blocked.
- Too much mucus is produced.
When the sinus openings become blocked and mucus accumulates, this becomes a great breeding ground for bacteria and other organisms.
Sinusitis usually follows respiratory infections, such as colds, or an allergic reaction. Some people never get sinusitis, and others develop sinusitis often.
People more likely to get frequent sinusitis include those with cystic fibrosis and those with immune systems weakened by HIV or chemotherapy.