Nasal glands continually create mucus which helps to moisten and trap unwanted particles. When a person gets a cold, has an allergic reaction or experiences hormonal changes, the nasal glands can secrete an abnormal amount of mucus. This excess discharge makes its way out of the sinus cavity by either running out of the nose or dripping in the back of a person's throat as post-nasal drip.
Common Cold
The common cold is caused by one of over 200 viruses that attack the body's immune system, according to the Mayo Clinic. As the body attempts to fight off the virus, the sinus cavity reacts by over-producing mucus, leading to post-nasal drip. There is no cure for the common cold but people use over-the-counter medications such as decongestants, antihistamines and pain relievers to treat their symptoms.
Temperature and Humidity
Cold temperature can cause the sinuses to secrete thin mucus that drips in the back of the throat, according to the American Academy of Otolaryngology. In the summer months, going from a warm and humid environment into a cold and dry air conditioned environment can result in nasal discharge or the sinus cavity becoming inflamed. During the winter months, the dry air can cause the sinuses to become stuffy, secreting thick mucus that drips in the back of the throat, according to the American Academy of Otolaryngology.
Allergies
Seasonal and environmental allergies can cause nasal secretions that lead to post-nasal drip. Seasonal allergies are allergies that develop during the springtime due to increased pollen and mold growth. Environmental allergies may include pet dander, household mold and dust mites. People commonly treat post-nasal drip from allergies with antihistamines, to reduce allergic symptoms. Talk to your doctor before taking any medication.
Structural Abnormalities
The American Academy of Otolaryngology states that structural abnormalities can cause chronic post-nasal drip. The most common abnormality is a deviated septum, in which the central nasal wall is crooked, causing improper drainage and a constant dripping in the back of the throat. A deviated septum is only corrected by surgery.
Nasal Polyps
Nasal polyps are small, non-cancerous growths in the sinus cavity. These growths can cause obstruction throughout the sinuses, preventing secretions from exiting the nose, causing a backup of fluid that drips in the back of the throat. Nasal polyps can be treated with prescribed medications or surgery, according to the Mayo Clinic.
