Runny Nose

Causes of runny nose

A runny nose is caused by inflammation of the nasal passage lining and blood vessels, typically from a viral infection such as the common cold. Allergies and sinus infections are also commonly associated with a runny nose.

Less common causes include obstructions in the nose from a foreign body or problems with the septum (the dividing wall between nasal passages). Environmental factors such as pollution can cause a runny nose and in rare cases in can be a sign of a tumour.

Other causes of a runny nose include:

• Cold weather
• Sudden drop in temperature
• Eating spicy food
• Enlarged adenoids (small tissue that hangs from the back of the nasal cavity)
• Tobacco smoke
• Hormonal changes
• Injury to the nose
• Nasal polyps
• Medications
• Drug use (cocaine)
• Cluster headaches

Symptoms of runny nose

The main symptom of a runny nose is a thin mucus out of the nasal passages (or running down the back of the throat). A runny nose can also be accompanied by:

• Blocked nose
• Sneezing
• Red, sore eyes
• Loss of smell
• Breathing problems
• Headache
• Fatigue
• Sinus pain

Diagnosis of runny nose

In most cases, a runny nose is mildly irritating and caused by something that doesn't require medical attention (such as a common cold). However, if symptoms are persistent then it could indicate a more serious underlying problem.

You should seek a medical opinion if:

• Symptoms are present for ten days or more
• You have a fever for more than three days
• The discharge from your nose is green in colour and accompanied by sinus pain or fever as this can indicate a bacterial infection
• You already suffer with asthma or emphysema
• You have blood in your nasal discharge
• Your child is under two months old and has a runny nose and fever

If your runny nose has been caused by a head injury then seek emergency medical attention.

Related terms

Cold
Stuffy nose
Cough
Sneeze
Congestion
Allergy
Dust
Hay fever
Pollen