Why does your nose run when it's cold outside?
You don't have to be sick to have the sniffles in the winter. In many cases, it means your nose is performing its job. It is through the nose that air is heated and moistened before entering the lungs. The blood-filled membranes that cover the bones of the nose protect them. Behind the nasal cavities, blood flows through these membranes, keeping the area warm.
Nasal membranes release water and mucus when exposed to cold air. Moisture drips down the walls like a little steam bath in a small room. The more water and mucus created as the air becomes colder and dryer, the more sniffles, and tissues are produced.
A warm shower or bath can also help dry up a runny nose and relieve your sinuses. Because you're already breathing moist, warm air, it allows the membranes to stop secreting mucus.
When you have a cold, your nose runs for a completely different reason. When you sneeze, your body creates a lot of mucus to flush out the bacteria that cause a cold. During a cold, mucus may change color due to the white blood cells that fight infection.
Antibiotics will do nothing to alleviate the symptoms of a cold, no matter what color it is. Instead, use a pain reliever or decongestant over the counter to relieve your symptoms. (Check with your doctor or read the labels to see if the ingredients are safe for you.) Take hot baths or showers on a frequent basis to aid in the drainage of your nose.