What is Post-Nasal Drip?
Postnasal drip (PND) is the drainage of secretions from the nose or paranasal sinuses into the pharynx 1.
Clinical Definition and Terminology
The ACCP guidelines define PND as secretions draining from the nose or paranasal sinuses backward into the throat 1. However, the medical community now recommends using the term "Upper Airway Cough Syndrome" (UACS) instead of "postnasal drip syndrome" when discussing cough associated with upper airway conditions 1. This terminology change reflects uncertainty about whether symptoms result from actual dripping secretions or from direct irritation/inflammation of upper airway cough receptors 1.
How Patients Experience It
Clinically, patients typically report:
- A sensation of something dripping down into the throat
- Nasal discharge
- Frequent throat clearing 1
Importantly, approximately 20% of patients with PND-induced symptoms are completely unaware of either the presence of postnasal drip or its connection to their symptoms 1. This "silent" postnasal drip is a critical diagnostic pitfall—patients may have the condition without recognizing the classic sensation.
Physical Examination Findings
On examination, suggestive findings include:
- Mucoid or mucopurulent secretions in the nasopharynx or oropharynx
- Cobblestoning of the pharyngeal mucosa 1
However, the absence of these findings does NOT rule out postnasal drip 1. The symptoms and signs are nonspecific, and no definitive diagnosis can be made from history and physical examination alone 1.
Underlying Causes
The differential diagnosis includes multiple conditions:
- Allergic rhinitis (seasonal or perennial)
- Perennial nonallergic rhinitis (vasomotor rhinitis)
- Postinfectious rhinitis
- Bacterial sinusitis
- Allergic fungal sinusitis
- Rhinitis from anatomic abnormalities
- Rhinitis from physical or chemical irritants
- Occupational rhinitis
- Rhinitis medicamentosa
- Rhinitis of pregnancy 1
GERD may occasionally mimic postnasal drip due to overlapping upper respiratory symptoms 1.
Diagnostic Approach
There is no objective test for postnasal drip and no way to quantify the amount of secretions or directly prove causation 1. The diagnosis relies on:
- Patient symptoms
- Physical examination findings
- Radiographic findings when indicated
- Most importantly: response to empiric therapy 1
The improvement or resolution of symptoms in response to specific treatment is the pivotal factor in confirming the diagnosis, making an empiric trial of therapy both diagnostic and therapeutic 1.
Clinical Significance
Postnasal drip/UACS is the most common cause of chronic cough in adults, either alone or in combination with other conditions 1. It is also a principal cause of cough associated with the common cold, making it the most common cause of acute cough as well 1.