Sinusitis is an infection of the para nasal sinuses that occurs due to obstruction or bacterial growth
. Among the many causes of such obstruction or congestion are common cold
, allergies, certain medical conditions, and abnormalities in the nasal passages. Sinusitis develops as follows:
* Mucous drainage
and airflow are blocked.
* Secretions build up, encouraging the growth of certain bacteria.
* The resulting infection, swelling, and inflammation create further blockage, which may cause the sinuses to close up completely.
Bacteria are the most common direct cause of acute sinusitis
. The ability of bacteria or other agents to infect the sinuses, however, must first be set up by conditions that create a favorable environment in the sinus cavities. The cause for chronic sinusitis
cases are sometimes unclear.