The body's nasal and sinus membranes have similar responses to viruses, allergic insults, and common bacterial infections.
Membranes become swollen and congested as increased blood passes through the nasal turbinate.
This congestion causes pain and pressure, mucus production increases during inflammation, resulting in a drippy, runny nose. These secretions may thicken over time, slowing their clearing and may predispose future bacterial infection of the sinuses. Congestion of the nasal membranes may even block the Eustachian tube leading to the ear, resulting gin a feeling of blockage in the ear or fluid behind the eardrum. Additionally, nasal airway congestion causes the individual to breathe through the mouth. This is uncomfortable because the nose is responsible for normal breathing, warming, filtering, and humidification of air that is inhaled.