The Face Hole Series

Photo: Trude Jonsson Stangel / Unsplash

Ever wonder why nasal mucus is called snot? It may sound rude, but it comes from the Old English word, gesnot, which dates back to the late 14th century and literally means nasal mucus. Snot has the same etymology as snout and snite, which means to “blow or wipe the nose.” It wasn’t until 1809 that it was used as an insult. We may laugh at both the word and the idea of snot but, trust me, breathing is better because we have boogers.

Snot is a vital part of our sinonasal system (see below). To understand its role, we have to first understand how the nose and sinuses work.

CDC website

Our noses and sinuses are holes in our heads that make our skulls lighter. (The average head already weighs eleven pounds. Imagine how huge our necks would have to be to hold up something heavier!) The average person has eight sinuses and one nasal cavity divided into two parts by a septum. They are lined with a very intricate mucosa that has three functions. It warms, humidifies, and filters the air we breathe. Although you can take in a bigger volume of air through your mouth, oxygen is absorbed into your lungs four times more easily if you breathe in through your nose.

For the sinonasal lining to do its job, it makes snot.

Snot is the slimy, sticky goo that traps the dust, dirt, and allergens you breathe in. It is made of 95% water and a combination of lipids, proteins, antibodies, and salts. Tiny hair-like projections on the lining, called cilia, move snot towards the back of your nose and down your throat. The average person makes about 34 ounces of snot a day–the equivalent of two grande coffees from Starbucks. Kind of like caffeine addicts, we swallow most of it without even realizing it.

If you have allergies or a cold, you make even more snot. The inflammation also slows your cilia so it spills forward to be claimed by Kleenex. Excess snot can also drip down the back of your nose–the dreaded post nasal drip–which causes throat clearing, soreness, and cough.

Snot can dry in your nose after it’s collected dirt and become squishy or crumbly. We often call this dried snot boogers, but more colorful terms exist, like salty cabbage and crusty dragon. Boogers are so ubiquitous that urban thesaurus lists no less than 265 alternatives. They can become so big they block your breathing until you sneeze or blow out the putrid treasure.

Too little snot can also be a problem. It can cause dry nose or just congeal into an inspissated glob. Dry nose can lead to worse allergy symptoms, colds, and bloody noses. Certain diseases, like Sjogren syndrome, cause dry sinuses. Medicines, like decongestants and antihistamines, can dry out your nose as do chemicals, smoke, and other irritants.

Photo: Steve Johnson / Unsplash

You can learn a lot about what’s going on in your body by the color of your snot. Clear means you’re healthy. White means you have a cold. Yellow is a sign of an early bacterial infection and green or brown means you let it go too far. Red or pink means there’s some blood mixed in. And black means you breathed in a lot of pollution or smoke. Snot that’s an unnatural color, like blue or purple, probably means you stuck something up your nose you shouldn’t have. When I used to treat children, I pulled out more than my share of shocking nasal surprises. Notable findings were tissues, bandaids, and even a screw.

Snot doesn’t do its job alone. It is densely packed with bacteria called the microbiome. The microbiome is a collection of trillions of microbes lining our entire respiratory and digestive tract. Think of the microbiome as a carpet of grass or a garden of wildflowers. When everything is in balance, the diversity of organisms keeps populations in check, even some that are known to cause disease. When the landscape changes, one bacteria can grow out of control. We don’t catch Streptococcus as much as catch viruses or have allergic reactions that change the environment in the “garden,” allowing one bacteria (Strep in this case) to overtake the rest.

Antibiotics kill down the overgrowth, but they also kill other healthy bacteria. When that happens repeatedly, yeast, another part of the microbiome that isn’t killed by antibiotics, can slowly fill in the gaps. Yeast overgrowth can lead to consistent inflammation and congestion. Doctors often mistake yeast for another bacterial infection and prescribe even more antibiotics, which makes everything worse. It’s hard to kill down the yeast because it has a three-month life cycle compared to one day for bacteria. I’ve had patients who’ve been on a revolving door of antibiotics for decades, and when I treat them with a two-week yeast cleanse, their symptoms completely resolve.

The next time you blow your nose, give pause before you throw out your tissue. Take a deep breath and show some gratitude. You may think all this talk of nasal mucus disgusting, but it’s snot.