(RxWiki News) The autumn can bring all sorts all cold, allergy and sinus symptoms. The nose during this time of year seems often to be either runny or stuffed up.
Perhaps instead of the nose actually being plugged up with mucus, we are only experiencing a type of sensory feedback about the temperature and humidity of the air we inhale.
"A stuffy nose may not be sinus congestion at all."
Scientists led by bioengineer Kai Zhao, Ph.D., at the Monell Center now report that the annoying feeling of nasal obstruction could be sensory feedback from inhospitable nasal airflow that adds to the feeling of congestion. This finding may help researchers design and test more effective treatments for this familiar symptom of nasal sinus disease.
Nasal sinus disease, usually caused by infection or allergies, is one of the most common medical conditions in the U.S. Approximately 33 million people deal with it each year, and nearly $6 billion is spent to try to treat the condition.
However, symptoms of nasal congestion are often difficult to treat because despite a patient's report of congestion, many doctors have found little relationship between reported congestion to actual physical obstruction of nasal airflow.
By establishing that feelings of nasal congestion can be related to the senses' response to the air conditions, the researchers are opening the door for more targeted treatment, says Dr. Zhao. For example, he adds, effective treatments for congestion may need to focus on restoring the right amount of humidity and the right temperature in the patient's airflow.
The study included some 45 healthy volunteers, who rated their symptoms of nasal congestion after breathing air from three boxes. One box contained room air at normal humidity. The second box contained dry air at room temperature, and the third contained cold air.
The participants reported reduced nasal congestion after breathing from both the cold air and the dry air boxes as compared with the normal humidity box. Breathing from the cold air box led to decreased reports of congestion most effectively.
These reports revealed that humidity, not just air temperature, is also an important factor, with lower humidity associated with decreased sensations of congestion.
The authors speculate that temperature and humidity interact as air moves through the nasal cavity to influence nasal cooling. It is this cooling that is then detected by "cool sensors" inside the nose to influence the feeling of air flow being either easy or obstructed.
Explains sensory scientist and study coauthor Bruce Bryant, Ph.D., "Someone in the desert, all other things being equal, should feel less congested than someone in the jungle. In the low humidity of the desert, there is more evaporative cooling inside of the nose, such that the temperature of the nasal passages is lower. This leads to a feeling of greater air flow -- and less sensation of obstruction."
Future studies will examine patients who report nasal obstruction to see if the sensory findings reported here can explain their symptoms and will also explore how sensory factors interact with other predictors of nasal obstruction.
The study appears in the journal PLoS One, The research was funded by the National Institute on Deafness and Other Communication Disorders.