There are many things that may cause a runny nose. The common cold, a type of respiratory infection caused by a virus, is one of the most likely culprits. It typically leads to a stuffy, runny nose, sore throat, and coughing; it may also cause a headache, low-grade fever, and appetite changes. Many people feel extra tired when they have colds as well. The common cold is highly contagious, but isn’t dangerous for most healthy people.
Sometimes allergies can cause a runny nose. For example, if a person is allergic to something like flowers or pollen, her nose will run whenever she has significant exposure to the allergen. The same goes for people who are allergic to cats and dogs. Their noses may run and they may have the urge to sneeze whenever these animals are in their presence.
Many people are most familiar with runny noses caused by allergies to things in the air, such as pollen and animal dander, but a runny nose can result from things people consume as well. For example, if a person is allergic to milk products, her nose may run when she consumes them. This is unlikely to be her only symptom, however. People with milk allergies often experience such symptoms as vomiting, hives, and wheezing. These symptoms may occur right away in some people; others may have symptoms that develop over a period of time, which include not only a runny nose, but also liquid-like and/or frequent bowel movements, cramps in the abdominal area, coughing, and rashes.
Bacterial infections can be responsible for a runny nose. If a person has a sinus infection, for example, her nose may run, and the nasal drippings may appear green or yellow and thick. Sometimes this drainage drips down the back of the throat in addition to exiting through the nose. A person with a sinus infection may also have difficulty breathing normally through her nose and experience pain in the area around the eyes, nose, and cheeks. She may suffer from fever, sore throat, nausea, and pain in the forehead, jaw, and teeth.
Discolored nasal drippings don’t always indicate a bacterial infection. Yellow or green mucus can be present with not only the common cold, but also other types of viral infections. However, a person may be able to tell the difference because she has a fever that is higher than that typical of viral infections. Additionally, her level of discomfort may alert her to the fact that she has something more than an everyday cold or run-of-the mill viral illness.
