My 7 year old daughter recently had some sort of cold and asked why she has a runny nose. I said it is how your body helps you fight a cold, to which she responded , “A runny nose isn’t helping me.”

This got me thinking exactly why/if a runny nose is indeed helpful.

With the cold season upon us and kids and adults everywhere sniffling, using tissues and sometimes sleeves or other creative parts of clothing to combat the seemingly never-ending mucous draining from their nostrils. I thought I could shed some light onto why at times we have impressive runny noses.

The medical term for a runny nose is Rhinorrhea.

I want to touch on viral/infectious causes in this brief article, realizing that other causes include allergens, crying, medications, disease processes and sometimes severe head injuries.

First I think it is important to realize that lining the nasal cavity are mucous producing cells whose purpose is to warm air and trap foreign particles from going all the way down to the lungs.

Your nose has several Concha that provide increased surface area for inhaled products to contact. Sometimes in cold weather moisture can form in the nasal passage simply from temperature differences much like a cold glass on a hot day accumulates moisture. This can cause runny /drippy nose shortly after being in cold weather.

This is a matter of physics and is best avoided by avoiding the trigger….not going in the cold. This is not a viral or bacterial process and has no lasting systemic effects.

A true cold (infectious source) has several possible reasons for Rhinorrhea. One evolutionary possibility is if a virus/bacteria can be trapped in mucous in th the nasal cavity rather than the alveoli (deep in the lungs) your body has a better chance of fighting it off. Rhinorrhea is better than a pneumonia.

How does our body know to produce absurd amounts of mucous? In short it is part of an immune response where the body identifies a virus or bacteria triggers the mucous cells lining the nasal passage to increase secretion ( causing runny nose). This response is why decongestants/antihistamines can help symptoms of a cold. These medications counteract/ block the bodies natural response, thus lessening symptoms.

I have heard on more than 1 occasion that the color of the mucous has diagnostic value. For instance a patient would say, ” my mucous ( buggers/snot) is green so I know I have an infection”. I would clarify this thought that normal mucous is usually more clear, but the shade of yellow or green itself does not equate to severity of infection. The color is commonly from white blood cells (the bodies immune cells) and can fluctuate during possible viral or bacterial infection as well as allergies. It is I do think worth noting that that the bodies immune system is involved, but color itself cannot reliably be used to diagnose bacterial vs viral etiology ( cause).

It is interesting to think that the common symptoms we experience like a runny nose are caused by our bodies response rather than the bacteria or virus itself. Sometimes people may think it is best to let the body react and not intervene. While I do like the thought that most of the time our body is doing things for a reason and it may be best to allow it that I am glad that we have things that can lessen effects of some things like runny noses.