why does a cold cause a runny nose


At this time of year, it can feel like everyone around you has a head cold. Decongestant medicine, tissues, and runny noses close in on all sides. But why does your nose run in the first place? The answer lies in the way your nose combats disease. The nose is a complex organвit warms and modifies air as it comes into your body, and acts as a gatekeeper against the external environment, says, a professor of otolaryngology at the University of Pittsburgh Medical Center. That means itвs a major battleground for the immune system as it works to protect your body from invading disease. Even when youвre not sick, your nose is lined with mucus. It traps disease-causing bacteria and viruses that might infect you if they reach more vulnerable body tissues. A layer of ciliaвthose hair-like structures that cover the interior of your noseвmoves that mucus from the front of your nasal passages towards the back and down your throat. When you\’re sick, itвs because pathogens have gotten past the mucus lining. To protect your body, the immune system kicks into action. Small proteins called cytokines deploy T cells and B cells to seek out and destroy the pathogens. Those same protein messengers instruct cells in the nose to generate more mucus in order to clear the cell lining of other potentially harmful bacteria or viruses.


As mucus goes into overdrive, your mucus lining swells and your nasal cavity fills with excess fluid. This can drip out of the nose itselfвa medical condition known as rhinorrhea, which the rest of us call a runny nose. Once your body clears the pathogens, your immune system will decrease its panic signals and your mucus lining returns to its usual level. Generally, Lee says, the immune system in your nose is very adept at identifying cells that the body makes to create your tissues and fluids (those are usually safe) from foreign cells that that need to be attacked. Sometimes, however, that system is not so great at knowing when to shut off its response, or at identifying which cells it should be attacking. Over-active or misdirected immune responses cause conditions like allergies or asthma–the body launches a full-scale attack at something that wouldn\’t really harm it, which causes damage to the body\’s own tissues. Be careful with your nose! Even when your body has discharged its invaders, the mucus carrying them is highly contagious. In other words, it can still transmit disease to others. You already know that frequently washing your hands is a great way to avoid getting sick, but Lee is emphatic about it: Touching your nose, mouth, or eyes without washing your hands can mean that disease-causing bacteria and viruses can infect (or re-infect) you more easily. \”As a doctor I see sick patients all the time, but I wash my hands constantly so that I donвt get sick,\” Lee says.


If you do get sickвand itвs unavoidable for many of us, Lee acknowledgesвitвs important to be careful with your nose. Blowing your nose too hard can damage the delicate cilia. It can even propel pathogens deeper into the nasal cavity, where they can further infect the body. Lee suggests treating a stuffed or runny nose by moistening the nasal lining with saline solution (through nasal sprays or irrigation tools like neti pots). This will help loosen the mucus and help bring it back to normal more quickly. You can also use a nasal decongestant drug. But donвt be surprised if your doctor doesnвt prescribe antibioticsвthe majority of colds are caused by some form of, which the body can get rid of in less than two weeks. If your symptoms get worse after that time, then maybe a bacterial infection has taken hold, in which case you
would require antibiotics, Lee says. All in all, having a runny nose might be annoying, but itвs a good sign. It means your immune system is doing its job. You\’re welcome. As the old joke goes, \”If your nose runs, and your feet smell, you\’re built upside down! \” Kidding aside, there are many reasons we get runny noses в technically known as rhinorrhea.

When you have a cold or the flu, the mucous membranes that line the cavities in your nose produce a combination of and fluid designed to fight off and wash away the germs. also produces extra mucus after exposure to an, whether it\’s pollen, animal dander, or something else. Crying hard can also cause excess liquid to drain from the duct in the inner corner of the eyelid into the nasal cavities and out through the nose. But why does your nose run when you\’re out on a chilly winter day, even when you\’re not sick or upset? Your Nose at Work Our noses warm and humidify в add moisture to в the air we breathe as it travels down into the lungs. So when you inhale cold, dry air, the moist tissue inside the nose automatically increases fluid production to do its job of protecting sensitive lung tissue. But when there\’s too much fluid, the excess tends to drip out, creating a runny nose. Winter has other effects that make it more likely youвll have a runny nose. Cold temperatures can cause the small water droplets inside the moist nose to join together, forming big, heavy drops of water that can also drip from your nostrils.

And cold air also speeds up. Could You Have Skierвs Nose? Researchers have a name for a related syndrome linked to exercising outdoors in cold weather: Not surprisingly, it\’s called skier\’s nose. A 1991 study published in the journal Annals of, Asthma and Immunology found that nearly 100 percent of skiers complained about runny noses while participating in their sport. While a runny nose is annoying in just about any season, it\’s not harmful. And if you\’re worried that you\’ll from being out in the cold, don\’t fret. That\’s a common myth, but experts believe the reason colds are more common in the winter is because we spend more time indoors around other people, who transmit their cold viruses to us by sneezing and leaving germs on surfaces that we touch. If you\’re really bothered by your winter runny nose, try taking an over-the-counter decongestant. The prescription nasal sprays Ru-Tuss and Atrovent have also been found to be effective at drying up drippy noses. Then there\’s always mom\’s advice: Before you go out in the cold, cover your nose and mouth with a scarf. Air breathed through fabric will be warmer and moister, which can cut down on those annoying drips. Do you have a health head-scratcher? , and we may answer your question in a future column! See.

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