Why Does Your Nose Run When You Have a Cold? - Newport Paper House


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Why Does Your Nose Run When You Have a Cold?

Having a runny nose is one of the most annoying and uncomfortable symptoms of the common cold. As mucus starts dripping out uncontrollably, you find yourself constantly reaching for tissues. But why does your nose produce more mucus when you're sick? Let's take a look at the reasons behind the runny nose.

The Role of Mucus

Mucus is a slimy substance that coats and moisturizes membranes in your nose, throat, mouth, digestive system, and other areas of your body. It's produced by goblet cells and submucosal glands in the mucous membranes.

Mucus acts as a protective barrier and trap for germs, dust, and other irritants that could harm your body. The mucus catches these particles, preventing them from entering deeper into your lungs and airways. The trapped irritants are then cleared out when you blow your nose or swallow the mucus dripping down the back of your throat.

So mucus plays an important role in keeping your respiratory system functioning smoothly and protecting you from infections. But when you have a cold, mucus production shifts into overdrive.

The Cold Virus Triggers Increased Mucus Production

When a cold virus infiltrates the cells in your nasal passages and throat, it causes inflammation and irritation. As part of your body's natural defense against the virus, your mucous membranes react by producing more mucus than usual.

This increased mucus production has a couple of purposes:

  • Attempt to flush out the virus - The boost in mucus production helps trap the cold virus in the mucus so that viruses can be expelled from your airways when you blow your nose. Mucus production ramps up to wash away viral particles.
  • Coat and soothe irritated membranes - The excess mucus also works to coat the mucous membranes lining your throat and nose, creating a protective layer between the irritated tissues and the air you're breathing in. The mucus acts as a soothing barrier against inflammation.

So in essence, your runny nose is your body's attempt to wash away the virus causing your cold and reduce the irritation in your nasal and throat membranes.

Specific Causes of Runny Nose During a Cold

In addition to the general inflammation reaction, a few specific biological processes make your nose run more when you have a cold:

1. Increased Blood Flow

When you catch a cold, blood vessels in your nose dilate to deliver protective white blood cells to the areas infiltrated by viruses. This influx of blood flow causes swelling in nasal tissues.

The swollen blood vessels put pressure on your nasal glands, causing them to secrete more mucus. More blood flow also stimulates the goblet cells in your nasal lining to produce extra mucus to lubricate and protect tissue.

2. Histamine Release

Histamine is a biological compound released by your immune system cells during an infection. The main role of histamine is to widen blood vessels and make capillaries more permeable so that more white blood cells can get to the site of infection.

Histamine also stimulates mucus secretion. When you have a cold, histamine levels rise in your nasal tissues, which triggers your mucous glands to secrete more mucus.

3. Prostaglandins

Prostaglandins are lipid compounds generated by mucous glands that have an inflammatory effect. They are released when the respiratory system is under attack from a virus.

Prostaglandins amplify mucus secretion, causing runnier discharge from your nose when you have a cold. They also heighten inflammation effects.

Other Factors Contributing to a Runny Nose

Some additional factors can worsen your runny nose when you already have excessive mucus production due to a cold:

  • Allergies - If you have indoor or outdoor allergies to pollen, dust mites, pets etc., these allergies can exacerbate nasal discharge when combined with a cold. Allergies also cause swelling, blood vessel dilation and increased mucus secretion.
  • Smoking and pollution - Irritants from cigarette smoke or air pollution can further inflame nasal tissue and stimulate mucus glands.
  • Dehydration - When you're sick, fluids thin out the mucus so it can drain properly. Dehydration leads to thicker mucus that's harder to blow out of your nose.
  • Spicy foods - Foods with hot spices or peppers can irritate mucous membranes and cause more nasal secretions.

So in summary, your nose runs excessively when you have a cold because your body is trying to flush out the virus and protect nasal tissues from damage. The cold virus triggers complex biological processes like increased blood flow, histamine release and prostaglandin production that stimulate mucus glands to produce extra mucus. Staying well hydrated, getting plenty of rest and avoiding irritants can help you manage an overactive runny nose.


A runny nose is one of the most common and pesky symptoms that comes with having a cold. But as annoying as it may be, that drippy nose is actually your body's defense mechanism hard at work, attempting to expel the viruses that are making you sick. Understanding the biological processes behind your runny nose can help you be more patient with this symptom as you recover. Drink lots of fluids, rest up, and grab the tissues - your runny nose will clear up as your cold runs its course!

FAQs About Runny Noses and Colds

  1. How long does a runny nose last with a cold?

A runny nose caused by a cold virus typically lasts between 7-10 days. In healthy individuals, the runny nose and excess mucus production should stop within 1-2 weeks as the cold runs its course.

  1. What medicine is best for a runny nose?

Over-the-counter antihistamines like Claritin or Zyrtec, and decongestant sprays like Afrin can help dry up excess nasal discharge. Nasal saline spray helps thin mucus. Avoid overusing decongestant sprays.

  1. When should you see a doctor for a runny nose?

See your doctor if your runny nose lasts longer than 10-14 days, mucus changes color, or you have severe headaches, fever, breathing difficulties or pain in your sinuses. These may indicate a sinus infection or other illness.

  1. Is it OK to blow your nose often when it's runny?

Yes, gently blowing your nose often is the best way to clear out excess mucus and cold viruses. Make sure to blow gently one nostril at a time and to wash hands afterward.

  1. What home remedies help with a runny nose?

Home remedies like steam inhalation, warm fluids, chicken soup, heated pads, and menthol rubs can provide relief for a runny nose. Saline nasal spray can help thin mucus. Resting, hydrating and getting extra sleep also helps.

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