When your nose starts to run, the first step in finding the right treatment is figuring out the cause. Three common causes of a runny nose are allergies, a cold, and a sinus infection.
If you are allergic to something (your allergen) such as tree pollen, your body mistakes that allergen for something harmful to your body. When you come in contact with the allergen, your immune system jumps into action by releasing antibodies and other chemicals to fight off the invader. One of these chemicals known as histamine causes the symptoms we associate with an allergic reaction including itchy or watery eyes and a runny nose.
Allergy symptoms show up after you have been exposed to your allergen. If you get away from the allergen, the symptoms should go away and your nose should stop running. Some allergens, like cat hair, tend to be localized. So if you visit someone with a cat you can expect a runny nose that will clear up when you get out of the area. But if you are allergic to something like tree pollen, you might notice your symptoms improving when you go indoors where the air is filtered.
Allergy treatments include antihistamines to reduce the allergic reaction. Many antihistamine or antihistamine/decongestants are available over-the-counter (OTC).
Seasonal allergies tend to show up around the same time each year, such as when a particular plant is pollinating. So if you suspect you have allergies, thinking about whether you always seem to get sick around the same time of year may help you figure out what your allergen is. An allergist can also do tests to determine what you are allergic to and can suggest treatments that may work better than OTC medications.
The common cold is caused by a virus and can be spread to other people. Symptoms of a cold include coughing, sneezing, sore throat, and a runny or stuffy nose. Common treatments include rest, pain relievers, and OTC cold medications. You can reduce the chances you will catch or share the cold virus by washing your hands often and always covering your nose and mouth when you sneeze or cough.