What is the best treatment approach for a patient with asthma presenting with a cough?

Treatment of Cough in Asthma

For any patient with asthma presenting with cough, immediately initiate combination therapy with inhaled corticosteroids plus inhaled bronchodilators—this is the first-line treatment regardless of whether cough is the sole symptom or accompanies wheezing. 1

Initial Treatment Regimen

• Start with inhaled corticosteroids (ICS) combined with an inhaled beta-agonist bronchodilator as first-line therapy for all patients with asthmatic cough, using standard doses equivalent to beclomethasone 200-800 mcg daily. 2, 1, 3

• Administer twice-daily dosing with proper inhaler technique, employing large volume spacers with metered-dose inhalers to optimize drug delivery. 3

• Expect partial improvement within 1 week, but complete resolution of cough may require up to 8 weeks of treatment with inhaled corticosteroids. 2

• Never use long-acting beta-agonists (LABAs) as monotherapy, as LABA monotherapy increases the risk of serious asthma-related events including death. 1, 4

Diagnostic Confirmation When Presentation is Unclear

• If physical examination and spirometry are non-diagnostic, perform methacholine inhalation challenge (MIC) testing to confirm bronchial hyperresponsiveness consistent with asthma. 2, 1

• A negative MIC test essentially excludes asthma from the differential diagnosis of chronic cough (negative predictive value approaching 100%). 2

• A positive MIC test is consistent with but not diagnostic of cough variant asthma—definitive diagnosis requires documented resolution of cough with specific antiasthmatic therapy. 2

• Consider measuring sputum eosinophil counts or fractional exhaled nitric oxide (FENO) to assess eosinophilic inflammation, which predicts corticosteroid responsiveness. 1, 3

Stepwise Escalation for Incomplete Response

When cough persists despite initial therapy, follow this sequential algorithm:

Step 1: Increase Inhaled Corticosteroid Dose

• Increase ICS dose up to a daily equivalent of 2000 mcg beclomethasone before adding additional agents. 1, 3

Step 2: Add Leukotriene Receptor Antagonist

• Add montelukast or another leukotriene receptor antagonist (LTRA) to the existing ICS and bronchodilator regimen after reconsidering alternative causes of cough. 1, 3
• Leukotriene inhibitors have demonstrated specific efficacy in suppressing cough previously resistant to bronchodilators and inhaled steroids. 1

Step 3: Short Course of Oral Corticosteroids

• Consider oral corticosteroids (prednisone 40 mg daily or equivalent) for 1-2 weeks only after the above steps fail, followed by transition back to inhaled corticosteroids. 2, 1, 3
• A 2-week course of oral prednisolone 30 mg daily serves both diagnostic and therapeutic purposes, as cough control is expected within 1-2 weeks if due to eosinophilic airway inflammation. 3
• No tapering is required for short courses of 1-2 weeks duration. 1

Step 4: Assess Airway Inflammation in Refractory Cases

• In patients whose cough remains refractory to inhaled corticosteroids, perform assessment of airway inflammation via induced sputum or BAL fluid. 2
• The demonstration of persistent airway eosinophilia identifies patients who may benefit from more aggressive anti-inflammatory therapy (higher dose inhaled corticosteroids or oral steroid therapy). 2

Critical Pitfalls to Avoid

• Do not use newer non-sedating antihistamines for asthma cough management—they are completely ineffective and should not be prescribed. 1

• Never jump directly to systemic corticosteroids without trying inhaled therapy first, as this exposes patients to unnecessary systemic side effects when inhaled medications are highly effective. 1

• Exclude alternative or contributing diagnoses before escalating therapy, particularly gastroesophageal reflux disease (which commonly coexists), ACE inhibitor use, and upper airway cough syndrome. 2, 3

• Assess medication compliance and inhaler technique before escalating therapy, as apparent treatment failure is often due to poor technique or non-adherence. 3

• Be aware that inhaled corticosteroids themselves may induce or exacerbate cough due to aerosol constituents—consider switching formulations if this occurs. 2

Monitoring and Long-Term Management

• Monitor for common inhaled corticosteroid side effects including oral candidiasis and dysphonia; advise patients to rinse mouth with water without swallowing after inhalation. 4

• Assess for decrease in bone mineral density initially and periodically thereafter, particularly in patients with multiple risk factors for osteoporosis. 4

• Monitor growth in pediatric patients receiving long-term inhaled corticosteroids. 4

• Consider referral to ophthalmology for patients on long-term inhaled corticosteroids due to risk of glaucoma and cataracts. 4

• Maintain long-term control with inhaled corticosteroids after any oral steroid course, and avoid repeated courses of oral steroids. 3