The most commonly reported causes of a runny nose and cough are viruses, primarily cold viruses and influenza. Some other causes may also result in these symptoms, such as allergies or hay fever. More severe illnesses can sometimes also lead to these symptoms, such as pertussis, although this is much less common.
There are over 200 types of cold virus and they are the most common cause of runny nose and cough, aside from seasonal allergies. They are highly contagious and spread easily from person to person through airborne particles which can be emitted into the air through coughing or sneezing. Colds can also be spread when someone wipes his or her nose or coughs into a hand and then touches a surface which is then touched by someone else.
Colds cause runny nose and cough by irritating the mucous membranes in the back of the throat and nasal passages. A runny nose helps to remove pathogens from the body by carrying them out through the mucus, and coughing forcefully clears any buildup of mucus in the back of the throat or in the lungs. Although annoying, these symptoms help to protect the body.
Seasonal allergies also commonly cause runny nose and cough, for much the same reasons as cold viruses. Allergens may cause irritations and inflammation in the nose, eyes, and throat. Symptoms occur because the body creates an immune response, much like that caused by a virus or bacteria, and acts to remove the substances. Common offenders include pollen, mold, pet dander, and dust.
In some cases, more serious viruses will cause a runny nose and cough. Influenza, for instance, may cause symptoms similar to those experienced during a cold, but more severe. Muscle aches and lung congestion are also common. Rarely a virus such as pertussis, or “whooping cough,” will result in runny nose and cough. This virus often starts out with cold-like symptoms and quickly progresses into a serious cough.
Any cough that becomes chronic or severe should be reported to a doctor. Illnesses such as pertussis and influenza can be potentially life-threatening to infants and the elderly, so prompt treatment is highly important. Viruses which cause the common cold usually clear up on their own with no medical treatment being necessary, while allergies may be seasonal or may require medication.
