Nasal spray oil are also available. There is however no trial-verified evidence that they have a measurable effect on symptoms. Decongestant nasal sprays are available over-the-counter in many countries. They work to very quickly open up nasal passages by constricting blood vessels in the lining of the nose. Prolonged use of these types of sprays can damage the delicate mucous membranes in the nose. This causes increased inflammation, an effect known as rhinitis medicamentosa or the rebound effect. Decongestant nasal sprays are advised for short-term use only, preferably 5 to 7 days at maximum. Some doctors advise to use them 3 days
Nasal concha (up to 98% water saturation) and filtered. The respiratory epithelium that covers the erectile tissue (or lamina propria) of the conchae plays a major role in the body's first line of immunological defense. The respiratory epithelium is partially composed of mucus-producing goblet cells. This secreted mucus covers the nasal cavities, and serves as a filter, by trapping air-borne particles larger than 2 to 3 micrometers. The respiratory epithelium also serves as a means of access for the lymphatic system, which protects the body from being infected by viruses or bacteria. The conchae provide, first and foremost, the humidity needed to