Medical Diagnosis for Sore Throat Due to Postnasal Drip
The medical diagnosis is Upper Airway Cough Syndrome (UACS), which is the current preferred terminology for what was previously called postnasal drip syndrome. 1
Diagnostic Terminology and Classification
Upper Airway Cough Syndrome (UACS) should be used instead of postnasal drip syndrome as it more accurately describes the condition. 1 The term UACS encompasses sore throat, throat clearing, and cough caused by drainage of secretions from the nose or paranasal sinuses into the pharynx. 1
Underlying Conditions That Cause UACS
The specific diagnosis depends on identifying the underlying rhinosinus condition causing the postnasal drip:
Rhinosinusitis - inflammation of the nose and paranasal sinuses characterized by nasal blockage/obstruction or nasal discharge (anterior/posterior nasal drip), with or without facial pain/pressure or reduction in smell 1
Acute rhinosinusitis - symptoms lasting less than 12 weeks with complete resolution 1
Chronic rhinosinusitis - symptoms persisting 12 weeks or longer without complete resolution 1
Allergic rhinitis - when triggered by allergens with associated sneezing, watery rhinorrhea, nasal itching, and itchy watery eyes 1
Non-allergic rhinitis - similar symptoms without allergic triggers 1
Clinical Presentation and Diagnostic Criteria
The diagnosis of UACS is primarily clinical and confirmed by response to specific treatment rather than objective findings alone. 1 Key diagnostic features include:
Cardinal symptoms: sensation of drainage in the throat, throat clearing, nasal discharge, and sore throat 1
Physical examination findings: mucoid or mucopurulent secretions in the nasopharynx or oropharynx, or cobblestoning of the oropharyngeal mucosa 1
"Silent" presentation: approximately 20% of patients have no obvious symptoms of drainage yet still respond to treatment directed at upper airway conditions 1, 2
Important Diagnostic Caveat
There is no objective test to quantify postnasal drip or directly prove it causes symptoms. 1 The diagnosis relies on a combination of symptoms, physical examination, and ultimately response to specific therapy. 1 An empiric trial of therapy is both diagnostic and therapeutic. 1
Pathophysiology
The mechanism involves increased viscosity of nasal secretions, impaired mucociliary clearance, and heightened nasopharyngeal sensitivity rather than simply increased secretion volume. 3 Research demonstrates that the sensation of postnasal drip may be due to mucosal inflammation resulting in heightened cough or irritant throat sensory dysfunction, not just mechanical irritation from secretions. 4, 5
Differential Diagnosis Considerations
When evaluating sore throat attributed to postnasal drip, consider: