The causes of chronic cough are very varied and are related to different systems.

In this article, we explain what postnasal drip is.

Because the postnasal drip triggers cough?

El postnasal drip, also known as postnasal drip syndrome, is a condition in which mucus produced in the nose or sinuses builds up and drains to the back of the throat instead of out the nose, resulting in several symptoms such as a “dripping” sensation in the throat.

The symptoms that are part of this syndrome are:

• Rhinorrhea: Dripping of mucus through the nostrils
• Burning or scratchy throat.
• Feeling of nausea caused by excess mucus in the stomach
• There is a frequent need to clear the throat.
• Secretions are spit out or swallowed
• Bad breath
• Cough, which worsens at night

The causes of a runny nose can be several, including:

• Rhinitis: It is the inflammation and swelling of the nasal mucosa, which causes increased secretion and congestion. It is often caused by respiratory infections and allergies.
  • Allergic rhinitis: It occurs when the immune system reacts to an environmental trigger such as dust or pollen. When these substances are inhaled, the person experiences itchy nose or eyes, sneezing, runny nose, and nasal congestion.
  • Non-allergic rhinitis: It is the inflammation of the nasal mucosa caused mainly by viruses, although there are more causes.
• Sinusitis: It is the inflammation of the paranasal sinuses due to infections or allergic reactions.
• nasal polyposis: They are fleshy proliferations of the nasal mucosa that form around the entrances to the paranasal sinus cavities.
• Adenoid hypertrophy
• Inflammatory and/or immunological diseases
• Tumors
• Presence of foreign bodies

Postnasal drip causes coughing because mucus dripping from the nose into the throat irritates the airways and cough receptors, triggering the cough reflex to clear the mucus. 

It's usually a short-term problem that resolves on its own over time, but if the cough is severe or persistent, it's advisable to consult a doctor. 

El postnasal drip It is one of the possible causes of cough. If it persists for more than 8 weeks, we are dealing with a case of chronic cough. 

Author: Eva Maroto

References:

1. Nieto Cabrera, ML, & Diego Damiá, AD (2001). A patient with a persistent cough. Med. Integral (Ed. impr), 250-256.
2. Chiu J, Rowan NR. Postnasal Drip. JAMA Otolaryngol Head Neck Surg. 2025;151(4):417. doi:10.1001/jamaoto.2024.5136
3. https://www.msdmanuals.com/es/professional/trastornos-otorrinolaringol%C3%B3gicos/trastornos-de-la-nariz-y-los-senos-paranasales/rinitis-no-al%C3%A9rgica?query=rinitis
4. https://www.msdmanuals.com/es/professional/trastornos-otorrinolaringol%C3%B3gicos/trastornos-de-la-nariz-y-los-senos-paranasales/sinusitis?query=sinusitis
5. https://www.msdmanuals.com/es/professional/trastornos-otorrinolaringol%C3%B3gicos/trastornos-de-la-nariz-y-los-senos-paranasales/p%C3%B3lipos-nasales?query=poliposo%20nasal