Treatment of Viral Post-Nasal Drip Cough in Moderate Asthma
For a moderately asthmatic patient with viral post-nasal drip and cough, start immediately with a first-generation antihistamine/decongestant combination (such as chlorpheniramine with sustained-release pseudoephedrine) as first-line therapy, and simultaneously optimize asthma control by ensuring the patient is on appropriate inhaled corticosteroid therapy. 1, 2
Initial Treatment Algorithm
Step 1: Address the Post-Nasal Drip (Days 1-14)
Begin with a first-generation antihistamine/decongestant combination as the most effective evidence-based treatment for upper airway cough syndrome, with specific effective combinations including dexbrompheniramine plus sustained-release pseudoephedrine or azatadine plus sustained-release pseudoephedrine. 1, 2
The anticholinergic properties of first-generation antihistamines are crucial for effectiveness in post-viral rhinosinusitis, making them superior to newer non-sedating antihistamines which have been shown to be ineffective for this condition. 1, 2
To minimize sedation, start with once-daily dosing at bedtime for a few days before increasing to twice-daily therapy. 1
Most patients show improvement within days to 2 weeks of initiating this therapy. 1, 2
Do not use antibiotics - they have no role in post-viral cough as the cause is not bacterial infection. 3, 2
Step 2: Optimize Asthma Management Simultaneously
Ensure the patient is on appropriate maintenance inhaled corticosteroid therapy for moderate asthma, as viral respiratory infections are a common trigger for acute asthma exacerbations. 4, 5
For moderate persistent asthma, the preferred treatment is the addition of long-acting inhaled beta2-agonists to low-to-medium doses of inhaled corticosteroids, which provides superior asthma control compared to increasing the ICS dose alone. 3, 6
Consider combination therapy with fluticasone propionate/salmeterol (Advair) which addresses both the inflammatory and bronchoconstrictive components of asthma with one inhalation twice daily. 6
Step 3: Add Intranasal Corticosteroids if No Improvement (Week 2)
If no improvement after 1-2 weeks with the antihistamine-decongestant combination alone, add intranasal corticosteroids such as fluticasone 100-200 mcg daily for a 1-month trial. 1, 2, 7
Intranasal corticosteroids are effective for both allergic and non-allergic rhinitis-related upper airway cough syndrome and work through multiple mechanisms including reducing inflammation and secretions. 1, 7
Maximum effect from intranasal corticosteroids may take several days, with some symptom relief occurring as soon as 12 hours after treatment. 7
Alternative Therapies for Contraindications
If the patient has contraindications to decongestants (uncontrolled hypertension, cardiovascular disease), use ipratropium bromide nasal spray (42 mcg per spray, 2 sprays per nostril 4 times daily) which provides anticholinergic drying effects without systemic cardiovascular side effects. 1, 2
Monitor blood pressure after initiating decongestant therapy, as decongestants can cause hypertension, tachycardia, insomnia, and worsening of glaucoma. 1
Management of Persistent Cough (Beyond 2-3 Weeks)
If Cough Persists Despite Upper Airway Treatment:
After 2 weeks of adequate upper airway treatment, proceed with sequential evaluation for other common causes of chronic cough, specifically asthma exacerbation and gastroesophageal reflux disease (GERD). 3, 1
Consider inhaled ipratropium bromide as it may attenuate persistent post-infectious cough, particularly if the cough has transitioned from subacute (3-8 weeks) to chronic. 3
If cough adversely affects quality of life and persists despite inhaled ipratropium, consider inhaled corticosteroids for the lower airway. 3
For severe paroxysms of cough after ruling out other common causes, consider prescribing 30-40 mg of prednisone per day for a short, finite period. 3
Central acting antitussive agents such as codeine and dextromethorphan should be considered only when other measures fail. 3
Critical Pathogenetic Factors in This Patient
In patients with subacute post-infectious cough and underlying asthma, multiple pathogenetic factors contribute including postviral airway inflammation with bronchial hyperresponsiveness, mucus hypersecretion, impaired mucociliary clearance, upper airway cough syndrome, and potential asthma exacerbation. 3
Approximately 20% of patients have "silent" post-nasal drip with no obvious symptoms yet still respond to treatment, so maintain a high index of suspicion even without classic symptoms. 1
The diagnosis of upper airway cough syndrome is confirmed by response to specific therapy, not by symptoms or physical findings alone. 1
Important Monitoring and Follow-Up
Reassess after 2-3 weeks of treatment with the antihistamine/decongestant combination to determine if additional interventions are needed. 1, 2
Complete resolution of upper airway cough syndrome may take several weeks to a few months, so maintain partially effective treatments rather than discontinuing them prematurely. 1
Common side effects of first-generation antihistamines include dry mouth and transient dizziness, with more serious side effects including insomnia, urinary retention, jitteriness, tachycardia, worsening hypertension, and increased intraocular pressure in glaucoma patients. 1
Monitor for signs of asthma exacerbation including increased albuterol use, nighttime symptoms, activity intolerance, and decreased peak flow measurements. 4
Adjunctive Supportive Measures
High-volume saline nasal irrigation (150 mL) improves outcomes through multiple mechanisms including improving mucociliary function, decreasing nasal mucosal edema, and mechanically rinsing infectious debris. 1
Adequate rest, hydration, warm facial packs, steamy showers, and sleeping with head of bed elevated can help alleviate symptoms. 2
Analgesics can be used as needed for discomfort. 2