In a way, it does. One of the primary causes of halitosis is post-nasal drip, and every spring millions Americans find their throats and palates coated with mucus caused by seasonal allergies.
Any nasal condition that increases mucus production has the potential to cause bad breath. Allergies are a surefire way to boost this production, according to the American Academy of Otolaryngology, Head and Neck Surgery.
However, a common misconception is that the smell of this oral odor comes from the drip itself. Instead, it is more accurate to say that a runny nose feeds anaerobic bacteria at the back of the throat, which in turn emit foul aromas as a byproduct of their digestion.
So what can be done about bad breath caused by post-nasal drip? Besides gargling with a specialty breath freshening rinse, individuals with this form of oral odor may consider trying Aktiv K-12 probiotics, which can replace smell-causing microbes with less harmful varieties.
Likewise, taking an over-the-counter allergy medication can reduce or even put a halt to post-nasal drip caused by hay fever, a condition that 17.7 million Americans are diagnosed with each year, according to the Centers for Disease Control and Prevention.