Finally, the fourth common cause is postnasal drip, which is most often the result of chronic allergic rhinitis. This is essentially an allergy to airborne particles like pollen, dust mites, mold spores, or animal dander. When you inhale something you’re allergic to, your body’s immune system overreacts by releasing histamine and other inflammatory chemicals.
These chemicals cause the membranes in your nose to swell and produce a large amount of thin, watery mucus to try and flush the allergen out. This is what we call a runny nose. However, this mucus doesn’t just run out of your nostrils; a significant amount of it drips backward down your throat. This is postnasal drip. When this happens chronically, the mucus can become thicker and stickier, creating that constant feeling of phlegm being stuck in your throat, especially at night when you’re lying down.
You should suspect allergic rhinitis if:
- Your symptoms are seasonal. Does your phlegm get worse in the spring or fall, when pollen counts are high?
- You have other allergy symptoms. Along with the phlegm, you’ll likely experience other classic signs of allergies, such as sneezing, a runny nose, and itchy, watery eyes.
- Your environment is a trigger. Do symptoms flare up when you’re around a cat, in a dusty room, or after being outside on a windy day?
If you think allergies are to blame, the first step is to identify and avoid your triggers. Simple home remedies can make a huge difference. Air out your home daily, but if you live in a polluted area or it’s high-pollen season, keep windows closed and consider using an air purifier. If dust mites are the issue, wash your bedding frequently in hot water and use anti-mite covers for your mattress and pillows.
