Q: Why does eating hot soup or spicy food cause a runny nose?
Dr. Dave says: It’s called vasomotor rhinitis, which is actually very common, and for a lot of people very annoying. Just as an FYI, the vasomotor refers to what in this case is a bit of an overreaction of the lining of your nostrils to some kind of irritation. (And any time you see “itis” on the end of a word, it refers to inflammation). So basically, when the lining of your nose is exposed to something that irritates it—and some people’s nostrils are more sensitive than others—you get an inflammatory response that starts with the tiny blood vessels inside your nose dilating and the cells in your nostrils secreting mucus. What you often wind up with is “rhinorrhea,” i.e. watery or “mucousy” drainage, congestion, sneezing, and itching.
What’s interesting is that lots of things can cause this, including odours (such as perfume, scented candles), alcoholic beverages, irritants (secondhand smoke, diesel exhaust), environmental factors (exposure to air conditioning or changes in air temperature), stress (emotional or physical), hormone changes (during menstruation, for example) and certain medications, many of which are in common use, among others.