What is the recommended management for post‑nasal drip?

Management of Postnasal Drip (Upper Airway Cough Syndrome)

Start immediately with a first-generation antihistamine/decongestant combination (such as chlorpheniramine plus sustained-release pseudoephedrine or dexbrompheniramine plus sustained-release pseudoephedrine) as the most effective evidence-based first-line treatment for postnasal drip, now termed Upper Airway Cough Syndrome (UACS). 1

Understanding the Condition

• UACS is the most common cause of chronic cough in adults, accounting for 18.6%–81.8% of cases 1
• Approximately 20% of patients have "silent" postnasal drip with no obvious nasal symptoms yet still respond to treatment, making empiric therapy both diagnostic and therapeutic 2, 1
• The diagnosis is confirmed by response to specific therapy rather than by physical examination findings alone 1
• Common underlying causes include chronic rhinitis (22%), chronic sinusitis/nasal polyps (31%), allergic rhinitis (28%), and adenoid vegetation (16%) 3

First-Line Treatment Algorithm

Initial Therapy (Days 1-14)

Start with first-generation antihistamine/decongestant combination:

• Dexbrompheniramine maleate plus sustained-release pseudoephedrine sulfate, OR
• Azatadine maleate plus sustained-release pseudoephedrine sulfate 1
• To minimize sedation, start with once-daily dosing at bedtime for a few days before increasing to twice-daily therapy 1
• Most patients will see improvement within days to 2 weeks 1

Critical point: Newer-generation antihistamines (cetirizine, fexofenadine, loratadine) are ineffective for non-allergic UACS and should NOT be used 1, 4

Add Intranasal Corticosteroids (If Allergic Rhinitis Identified)

• If allergic rhinitis is the underlying cause, add intranasal corticosteroids (fluticasone 100-200 mcg daily) immediately alongside the antihistamine/decongestant 1, 4
• For non-allergic causes, intranasal corticosteroids should be added only if no improvement after 1-2 weeks with antihistamine/decongestant alone 1
• A full 1-month trial is necessary to assess response 1

Alternative for Contraindications

If decongestants are contraindicated (hypertension, glaucoma, urinary retention):

• Use ipratropium bromide nasal spray 42 mcg per spray, 2 sprays per nostril 4 times daily 1
• This provides anticholinergic drying effects without systemic cardiovascular side effects 1

Adjunctive Therapy

High-volume saline nasal irrigation:

• Use 150 mL per nostril twice daily 1
• More effective than saline spray because irrigation better expels secretions 1
• Works through mechanical removal of mucus, enhanced ciliary activity, and disruption of inflammatory mediators 1

Critical warning: Never use topical nasal decongestants (oxymetazoline, xylometazoline) for more than 3-5 consecutive days due to risk of rhinitis medicamentosa (rebound congestion) 1

Treatment Based on Underlying Cause

Allergic Rhinitis

• First-line: Nasal corticosteroids + antihistamines and/or cromolyn 1
• Oral leukotriene inhibitors (montelukast) can decrease symptoms 1, 4
• For moderate-to-severe cases, combination intranasal fluticasone plus intranasal azelastine provides 40% relative improvement over monotherapy 4

Non-Allergic Rhinitis

• First-line: Older-generation antihistamine plus decongestant combination 1
• Nonsedating antihistamines are less effective for non-allergic rhinitis than for allergic rhinitis 1

Chronic Sinusitis

• If air-fluid levels on imaging or purulent discharge >10 days with facial pain/fever: antibiotics for minimum 3 weeks effective against H. influenzae, mouth anaerobes, and S. pneumoniae 1
• Continue intranasal corticosteroids for 3 months after cough resolution to prevent recurrence 4

When to Escalate Treatment

If no improvement after 2 weeks of adequate upper airway treatment:

1. Evaluate for asthma/cough-variant asthma:

   • Perform bronchoprovocation testing or empiric trial of inhaled corticosteroids 1

2. Evaluate for GERD (frequently mimics UACS):

   • Initiate proton pump inhibitor (omeprazole 20-40 mg twice daily before meals) for at least 8 weeks plus dietary modifications 1, 5
   • Improvement in cough from GERD treatment may take up to 3 months 1
   • PPI therapy significantly improved postnasal drainage symptoms in patients without sinusitis or allergies (50% improvement vs 5% with placebo at 16 weeks) 5

3. Obtain sinus imaging (CT):

   • Only if persistent nasal symptoms despite topical therapy, purulent discharge with facial pain/pressure, or suspected complications 1
   • Routine imaging is NOT required for diagnosis 1

Monitoring and Side Effects

Common side effects of first-generation antihistamines:

• Dry mouth and transient dizziness 1

More serious side effects to monitor:

• Insomnia, urinary retention, jitteriness, tachycardia 1
• Worsening hypertension—monitor blood pressure after initiating decongestant therapy 1
• Increased intraocular pressure in glaucoma patients 1

Critical Pitfalls to Avoid

• Do not overlook "silent" UACS: Absence of visible postnasal drainage or cobblestoning does not rule out UACS 1
• Do not rely solely on physical examination: Symptoms and clinical findings are not reliable discriminators; therapeutic response is the pivotal diagnostic factor 2, 1
• Do not confuse GERD with UACS: Both can cause pharyngeal inflammation and throat symptoms and frequently coexist 1, 6
• Do not use newer antihistamines for non-allergic causes: They are ineffective for non-allergic UACS 1
• Maintain all partially effective treatments: UACS, asthma, and GERD together account for approximately 90% of chronic cough cases and often coexist 1

Follow-Up and Referral

• Schedule follow-up visit 4-6 weeks after initial evaluation to reassess cough severity and verify treatment adherence 1
• If cough persists beyond 8 weeks despite systematic treatment of UACS, asthma, and GERD, consider referral to specialized cough clinic 1
• Consider bronchoscopy referral if all empiric therapies fail to investigate less common etiologies 1

Red-Flag Symptoms Requiring Immediate Re-Evaluation

• Hemoptysis 1
• Progressive worsening of cough-related symptoms 1
• Difficulty swallowing or toxic appearance (rule out diphtheria or abscess) 7