What Causes a Cold?
In the simplest explanation, viruses cause colds. Virus-related germs enter through the nose, mouth, or breaks in the skin. Once the virus is inside your body, it finds a host cell to infect. One of the most common symptoms people experience during a cold is a runny nose. That’s because mucous glands go into overdrive to trap viral intruders and wash the germs away from the nose and sinuses. Once this happens, the immune system is better prepared to fight back.