The excess mucus production that triggers postnasal drip has a number of possible causes, including:
• Colds
• Flu
• Allergies (called allergic postnasal drip)
• Sinus infection or sinusitis (inflammation of the sinuses)
• Object stuck in the nose (more common in children)
• Pregnancy
• Certain medications (including birth control pills and blood pressure medications)
• Deviated septum (abnormal placement of the wall that separates the two nostrils) or another anatomical problem that affects the sinuses
• Changing weather fronts, cold temperatures, or excess dryness in the air
• Certain foods (for example, spicy foods can trigger mucus flow)
• Fumes from chemicals, perfumes, cleaning products, smoke, or other irritants

Sometimes the problem is not that you’re producing too much mucus, but rather that it’s not being cleared away effectively. Swallowing problems can cause a buildup of liquids in the throat, which can feel like postnasal drip. These problems can occur with age, a blockage, or conditions such as gastroesophageal reflux disease (GERD).

Symptoms of Postnasal Drip
Postnasal drip creates an annoying feeling that makes you want to constantly clear your throat. Because the feeling of the liquid in your throat is irritating and contains inflammatory substances, postnasal drip also can trigger a cough, which often gets worse at night. In fact, postnasal drip is the most common cause of chronic cough. Excess mucus running down your throat may also make you feel hoarse and give you a sore throat.

If the mucus plugs up the Eustachian tube — the tube that connects the throat to the middle ear — it can lead to a painful ear infection. When mucus blocks the sinus passages, it can lead to a sinus infection.

Treatments for Postnasal Drip
Treatment for postnasal drip depends on the cause of the problem. Bacterial infections are treated with antibiotics. However, green or yellow mucus is not necessarily proof of a bacterial infection. Colds can also turn the mucus these colors and they are caused by viruses, which don’t respond to antibiotics.

Antihistamines and decongestants can help with postnasal drip caused by sinusitis and viral infections. They can also be effective, along with steroid medications or nasal sprays, for postnasal drip caused by allergies. The older, over-the-counter antihistamines (Benadryl, Chlor-Trimetron) might not be the best choices for postnasal drip, because when they dry out mucus, they can actually thicken it. The newer generation of antihistamines (Clarinex, Allegra, Xyzal) may be better options, and are less likely to cause drowsiness. It’s a good idea to check with your doctor before treating your postnasal drip because all of these medications can have side effects that range from dizziness to dry mouth.

Another treatment option for postnasal drip is to thin your mucus. Mucus can have different consistencies. Thick mucus is stickier and more likely to cause you discomfort. Keeping the mucus thin helps prevent blockages in the ears and sinuses, which can lead to infections. A simple remedy to thin mucus is to drink more water.

Other methods you can try include:
• Taking a mucus-thinning medication such as guaifenesin (Mucinex)
• Using saline nasal sprays or nasal irrigation (such as a neti pot) to flush excess mucus, bacteria, allergens, and other irritating substances out of the sinuses
• Turning on a vaporizer or humidifier to increase the moisture in the air

Try propping up your pillows at night so that the mucus doesn’t pool or collect in the back of your throat. If you have allergies, ways to reduce your triggers include:
• Covering your mattresses and pillowcases with dust-proof covers
• Washing all sheets, pillowcases, and mattress covers often in hot water
• Using special HEPA air filters in your home
• Dusting and vacuuming regularly

Call your doctor if the nasal drainage is foul smelling, you have a fever, you’re wheezing, or your symptoms last for 10 days or more, because you might have a bacterial infection. Let your doctor know right away if you notice blood in your postnasal drip. If medication isn’t helping your postnasal drip, you might need to see an otolaryngologist for evaluation, which can include a CT scan, X-rays, or other tests.