Chronic sinusitis is the presence of constant nasal and sinus symptoms for three months or longer.
There are four pairs of sinuses.
The ethmoid sinus is a matchbox-sized area filled with 7 to 10 interconnected bubbles made of very thin-walled bone. These bony bubbles are lined with a mucous membrane similar to that found in the nose. Each bubble has its own opening to drain into the nasal, or nose, cavity. The front part of the ethmoid is the most crucial of all the sinuses because the forehead and maxillary sinuses must drain through it into the nose. The back part of the ethmoid drains through a separate opening.
The sinuses are normally air-filled. The lining of the sinuses are covered with microscopic fingers known as cilia that direct the mucus to the drainage openings.
The function of the sinuses is not clearly understood. In the average healthy person, the lining of the sinuses and nose makes about 1 to 1 1/2 pints of mucus each day. One of the functions of the sinuses is to moisten, cleanse and warm the air as it goes through the nose before it enters the lungs. The healthy nose is a wonderful filter removing eighty percent (80%) of all tiny particles as they are breathed in. Since the sinuses are air-filled, another function is thought to be making the skull lighter in weight
Chronic sinus disease affects thirteen percent (13%) of the US population. or about 30-40 million people, according to the National Center for Health Statistics. In cases of chronic sinus disease, the natural drainage pathways of the sinuses do not always work properly.
Conditions in the environment like dry air, pollutants, dust and dirt can damage the microscopic "fingers" so that mucus is not cleared, and bacteria overgrow.
People with chronic sinusitis, regardless of the cause, are more likely to develop episodes of acute sinusitis, as well.