The presence of excess phlegm or mucus in the throat is caused by allergic postnasal drip, colds and flus, sinus infections, and excess dryness in the air, according to WebMD. Fumes from cleaning products, environmental irritants, chemicals or smoke can also trigger phlegm to flow into the throat.
An inflammation of the sinuses, a deviated septum and pregnancy cause excess phlegm to gather in the throat, explains the WebMD. Certain medications such as blood pressure medication and birth control pills can also cause phlegm or mucus to drip into the throat. Certain foods, such as hot or spicy dishes, increase the flow of phlegm and mucus as well.
Mucus or phlegm that is not cleared away properly can cause excess within the throat, according to WebMD. People who are unable to swallow phlegm experience a buildup of liquids and mucus in the throat, which commonly feels similar to postnasal drip. Difficulty swallowing phlegm can be caused by a blockage, age or medical conditions such as a reflux disease.
Treatments for excess phlegm in the throat is focused on the cause of the condition, explains WebMD. Physicians may prescribe decongestants or antihistamines to treat viral infections or sinusitis that causes excess phlegm or antibiotics, nasal sprays or steroid medications to treat allergies or infections.