Let’s talk about snot
It may be unsightly, but it’s a key part of a healthy immune system
It’s icky and messy and sometimes it clogs your airways, making you feel like you can’t breathe. Heck, even its name is repugnant. We’re talking about snot here. Yeah, grim topic. But with cold and fl u season looming, snot — or nasal mucus, as it can be more delicately described — is something many of us will experience fi rst- hand in the not-too-distant future. Here are some things you may not know about this decidedly disgusting bodily fl uid:
THE BASICS
Snot is what’s known as the mucus blanket of the mucus membranes of the nasal passages and the sinuses. For those tissues to do their jobs properly, they need nasal mucus. The mucus is made by glands in your nasal passages; goblet cells, to be precise. It’s mostly water — 95 per cent in fact, says Dr. John Lee, a head and neck surgeon at Toronto’s St. Michael’s Hospital. The remaining fi ve per cent is made up of proteins, salts and cells from the immune system. The human body produces one to two litres of nasal mucus every day. If you are having a hard time picturing that, think about the milk cartons in your fridge.
A NATURAL FILTER
The nasal passages are lined with tiny little hairs called cilia. Nasal mucus sits on top of those hairs, keeping them moist so they operate properly. It also humidifies the air we breathe in. The mucus is like a fly paper strip. Impurities in the air you draw into your nasal passages — things like dust, pollens, and other debris — stick to the mucus so they don’t get into your lungs. Those little hairs, the cilia, wave in a conveyor belt motion, moving the mucus toward the back of your nasal passages and into your throat. You swallow it and the gastric acids in your stomach neutralize anything the mucus is carrying. This is one of the basic weapons in your body’s protective arsenal, keeping you healthy.
WHEN WE GET SICK ...
When we are infected with something that triggers a cold — generally a virus — our production of nasal mucus increases. Depending on how bad the cold is, we can feel like we’re drowning in gallons of snot — like we’ll be blowing our noses forever. Furthermore, the immune system responds to an infection by sending more blood to the tissues in your sinuses and nasal passages. Those tissues swell as a result, contributing to the feeling of congestion, says Dr. Allan Vescan, a head and neck surgeon at Toronto’s Mount Sinai Hospital. White blood cells, a critical component of the immune system, also move into the area. This infl ammation of the nasal tissues stimulates increased production of nasal mucus and changes the quality of what comes out when you blow.
CHANGES IN COLOUR
Some of the enzymes produced when white blood cells break down contribute to the change in colour you might see in your nasal mucus during a cold, Vescan says. It may become yellow, or even greenish. Both Lee and Vescan say some patients read those changes as a signal, thinking coloured mucus is evidence of a bacterial infection that may require treatment with antibiotics. But that’s not necessarily so. “Discoloured mucus is defi nitely a sign of something happening. And yes, patients do interpret discoloured mucus as infection and often think it needs an antibiotic,” Vescan says. “But we don’t use the colour of the mucus as our guide for when to give antibiotic. It’s usually the amount of time the patient has had symptoms and the severity of the symptoms that will often guide that.”
WHAT TO DO?
If nasal mucus remains discoloured for seven days or longer — especially if the colour gets deeper — then suspicion grows that a bacterial sinus infection may be at work, Lee says. “At that point I would say it’s worthwhile seeking medical attention.” Otherwise, the options are relatively limited. You can keep plenty of tissues handy. You can use a saline nasal spray or a nasal rinse, provided you use distilled or boiled water. Nasal decongestants can be used, but with caution: prolonged use can cause both rebound and also more deleterious eff ects to the lining and the health of the nose and the sinuses.