Common Causes of a Runny Nose | Telfast Australia
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Why do I have a runny nose?

Published on April 12, 2018

Why do I have a runny nose?

A runny nose is an annoying nuisance that we have all experienced at some time or another. It is the excess drainage produced by the nose and surrounding blood vessels and can be thin and clear mucus or thick mucus. This excess mucus isn’t just there to annoy you, it actually has a useful purpose. Mucus traps bacteria and debris from entering your lungs getting rid of it, in this case through your nose! The mucus from a runny nose can run out of your nose or down the back of your throat, or both. When it runs down the back of your throat it is known as “post-nasal drip.” Sometimes you may also have nasal congestion along with your runny nose, but not always. A runny nose is sometimes known as “rhinorrhea” or “rhinitis.” There are some common causes of a runny nose, and if we know what is causing this annoying symptom it can also help us to manage it. A runny nose can be caused by anything that inflames and irritates the tissue in and around the nose. Bugs such as the common cold and flu, allergies and other irritants are all common causes of a runny nose.

Although there are many potential causes for a runny nose, some of the most common ones are:

Cold and flu

The common cold is due to a virus infecting the nose and throat. There are more than 100 different viruses that can cause the common cold. The flu is due to a virus that attacks the nose, throat and lungs and is more serious than the common cold. A runny nose is a very typical symptom of both cold and flu because the body is making extra mucous to try to protect itself.

Hayfever and Allergies

You may experience a runny nose if you are allergic to certain substances and are exposed by touching, inhaling or ingesting them. Allergies are caused by an overactive immune system, where the body mistakes a harmless substance as dangerous and then goes into overdrive and ‘attacks’ it, triggering an allergic reaction. Typical substances which trigger allergies are dust mites, pollen, animal fur, fungal spores, grass and mould. Your body reacts to the ‘allergens’ which results in the common symptom of a runny nose. Other common symptoms include itchy and red eyes and throat, sneezing and fatigue. Hayfever, also called allergic rhinitis, is a common type of allergic reaction. Hayfever usually occurs in Spring and on windy days due to the excess pollen in the air.


When the passages of the nose, also known as sinuses, become swollen and inflamed they can result in Sinusitis. The nasal passages may become narrowed which can cause difficulties with breathing and a build-up of mucus. The mucus can drain out of the nose or it may be felt in the back of your throat as a post-nasal drip. This type of runny nose usually is associated with thick mucus which can also have a yellow or green hue to it. Headaches are often experienced with Sinusitis also.

Other causes of a runny nose include:

  • Food allergies – common culprits are wheat, shellfish, peanuts, milk and soy
  • Pregnancy
  • Cluster headache
  • Colder temperatures and sudden temperature changes
  • Dry air
  • Hormonal changes
  • Medications
  • Nasal polyps
  • Other environmental irritants such as perfume and tobacco smoke.

Once you have determined to cause of your runny nose you can then treat it accordingly. If your runny nose is allergy related, an over-the-counter antihistamine such as Telfast may help to ease the symptoms. Other simple strategies for relief can include sniffing and swallowing, or gently blowing your nose. For a postnasal drip, where excess mucus has accumulated in the back of the throat, it may be useful to drink plenty of water, and use a humidifier. Also avoid common irritants such as tobacco smoke and sudden temperature changes. If your runny nose is due to a cold or flu, rest and fluid are key. For advice on treatment options for a runny nose please consult your healthcare professional.

For more information, visit the ASCIA website.

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