Postnasal drip is when the sensation of mucus buildup at the back of the throat causes discomfort. The nose, throat, and sinuses are all constantly producing mucus. Mucus is a thick and slippery substance that helps to keep the airways from drying out throughout the day. The air people breathe is full of germs, pollen, and other environmental pollutants. When the air enters the body, these particles can create problems if they are not filtered out. It is the job of mucus to trap these foreign bodies and help eliminate them.

Mucus usually goes unnoticed. It harmlessly mixes with saliva throughout the day and is swallowed or blown from the nose. However, if the body produces too much mucus, it becomes much more noticeable. When this happens, a person may feel mucus dripping down the back of their throat. This is what is known as postnasal drip.

Symptoms

In addition to the sensation of mucus dripping down the back of the throat, symptoms of postnasal drip include:

• sore or scratchy throat
• feelings of nausea caused by extra mucus in the stomach
• excessive spitting up or swallowing mucus
• foul breath
• a cough that gets worse at night

Causes

Postnasal drip is usually caused by certain changes in the environment or the body. One of the most common causes of postnasal drip is an allergy. Seasonal allergies caused by plants releasing their pollen may cause trigger postnasal drip, as the body produces extra mucus to try and eliminate the pollen spores. Cold weather or dry air can also cause postnasal drip. Breathing cold or dry air may irritate a person’s nose and throat, so their body will create mucus to humidify and warm the passages and ease this irritation. Cold weather is also associated with viral infections, such as the flu, sinus infections, and the common cold. These infections cause many symptoms, including postnasal drip. The body reacts to any invading germs by creating more mucus to flush them out. It may be uncomfortable, but it is actually the sign of the body working to stay healthy.

Other causes of postnasal drip include:

• eating overly spicy food
• pregnancy
• objects stuck in the nose
• irritating chemicals from perfumes, cleaning products, or environmental fumes
• medications, including birth control and blood pressure medications
• chronic respiratory conditions, such as COPD
• smoke