What causes throat clearing?

Throat Clearing: Causes and Clinical Approach

Primary Cause

Upper Airway Cough Syndrome (UACS) is the leading cause of chronic throat clearing, accounting for the majority of presentations either alone or in combination with other conditions. 1

Common Etiologies

Upper Airway Cough Syndrome (UACS)

• UACS represents the most frequent cause of throat clearing, characterized by the sensation of mucus drainage and frequent need to clear the throat 1
• Approximately 20% of patients with UACS have "silent" postnasal drip—they are completely unaware of drainage yet still respond to treatment 1
• The underlying causes of UACS include:
  • Allergic rhinitis (characterized by nasal itching, sneezing, clear rhinorrhea, and seasonal patterns) 1
  • Perennial nonallergic rhinitis (vasomotor rhinitis) 1
  • Postinfectious rhinitis 1
  • Chronic sinusitis 1
  • Rhinitis from irritants 1

Viral Upper Respiratory Infections

• Cough associated with the common cold is an upper airway cough syndrome often accompanied by throat clearing and the sensation of postnasal drip 2
• Viral infections cause vasodilation and hypersecretion in the respiratory tract, contributing to throat clearing symptoms 3
• The typical course lasts less than 3 weeks, though symptoms can persist as postinfectious cough (3-8 weeks) 3

Gastroesophageal Reflux Disease (GERD)

• While historically considered a common cause, recent objective evidence shows throat clearing has a low probability of association with GERD 4
• When throat clearing is the only presenting symptom, it is unlikely to be associated with GERD 4
• However, older literature suggests throat clearing may occur in patients with laryngopharyngeal reflux, though pharyngeal erythema alone is non-specific and should not be used to diagnose LPR 1, 5, 6

Other Causes

• Ciliary dysfunction (primary or secondary to viral infection) can contribute to recurrent throat clearing and ineffective mucus clearance 2
• Secondary ciliary dysfunction from acute viral infections may persist for weeks after the initial infection 2
• Aspiration risk: Patients with throat clearing accompanied by coughing during or after swallowing should be evaluated with a water swallow test 1

Diagnostic Approach

Initial Assessment

• Focus history on timing and pattern, associated symptoms (nasal itching, sneezing, rhinorrhea), triggers, and family history 1
• Physical examination should assess for cobblestoning of the posterior pharynx and visible secretions 1
• Do not rely on patient awareness of postnasal drip, as 20% with UACS are unaware of drainage 1

First-Line Empiric Treatment

• Initiate a first-generation antihistamine/decongestant combination for 2-4 weeks, even when patients lack obvious upper respiratory symptoms 1
• First-generation antihistamines are superior to second-generation agents due to anticholinergic effects that reduce secretions 1

If Allergic Rhinitis Suspected

• Add intranasal corticosteroids as primary therapy 1
• Consider specific IgE testing (skin or blood) if diagnosis is uncertain or empiric treatment fails 1

If No Response to Initial Treatment

• Evaluate for multiple simultaneous causes, as UACS, allergic rhinitis, and asthma frequently coexist 1
• Consider postinfectious cough if symptoms follow a recent viral illness 2, 3
• Assess for aspiration risk in high-risk patients (neurologic disease, elderly) 1

Critical Clinical Pearls

• Multiple conditions often coexist—treating all identified conditions simultaneously is crucial 1
• Avoid prolonged use of topical decongestants (>3-5 days) to prevent rhinitis medicamentosa, which causes rebound congestion 1
• For postinfectious throat clearing following viral infection, inhaled ipratropium may be helpful 3
• GERD should not be the first consideration when throat clearing is the only symptom, given low objective association rates 4
• Evaluate for sleep apnea if snoring is present, as nasal obstruction increases apnea-hypopnea events 1