A runny nose, also known as rhinorrhea, happens when the nose produces more mucus than usual. This excess mucus can be a sign of your immune system working to fight off an infection, or it can be caused by irritants like allergies or dry air.
Here are some common reasons why your nose might run:
- Infections: Colds, the flu, and sinusitis (sinus infection) are all common causes of runny noses. These infections irritate the nasal lining, causing it to produce more mucus.
- Allergies: Allergic reactions, such as those to pollen, dust, or pet dander, can also trigger a runny nose. The body releases histamine in response to the allergen, which causes inflammation and increased mucus production.
- Dry air: Cold weather or low humidity can dry out the nasal passages, leading to irritation and a runny nose. Your nose produces more mucus in an attempt to moisten the air you breathe.
- Nonallergic rhinitis: This condition, also known as vasomotor rhinitis, causes a runny nose without a known allergy or infection. The exact cause is unknown, but it may be related to changes in temperature or humidity, or even spicy food.
If you have a runny nose that doesn't go away or is accompanied by other symptoms like fever, headache, or facial pain, it's important to see a doctor to determine the underlying cause and receive appropriate treatment.
