What is the recommended treatment for cough variant asthma (CVA)?

Treatment of Cough Variant Asthma

Inhaled corticosteroids (ICS) are the first-line treatment for cough variant asthma and should be initiated immediately upon diagnosis. 1, 2

Initial Treatment Strategy

• Start with inhaled corticosteroids as monotherapy at standard doses (equivalent to beclomethasone 200-800 μg daily or fluticasone propionate 100-250 μg twice daily) 1, 2
• Use twice-daily dosing with proper inhaler technique, employing spacers with metered-dose inhalers to optimize drug delivery 2
• Continue treatment for 4-8 weeks to assess response 1, 2
• Beta-agonists can be added to ICS but should not be used as monotherapy, as cough variant asthma is typically bronchodilator-resistant 1, 3

The evidence strongly supports ICS as first-line therapy, with multiple studies demonstrating complete cough resolution in 80-90% of patients within weeks of initiating treatment. 4, 5, 6 This is a Grade 1B recommendation based on the stepwise asthma treatment evidence base. 1

Stepwise Escalation for Incomplete Response

If cough persists after 4-8 weeks of initial ICS therapy:

• Step 1: Increase the ICS dose up to high-dose (equivalent to beclomethasone 2000 μg daily) 1, 2
• Step 2: Add a leukotriene receptor antagonist (such as montelukast 10 mg daily) to the ICS regimen 1, 2
• Zafirlukast has demonstrated efficacy even in patients whose cough was refractory to inhaled steroids and bronchodilators 1
• Step 3: Consider a short course of oral corticosteroids (prednisone 20-60 mg daily for 1-2 weeks) for severe or refractory cases, followed by maintenance with high-dose ICS 1, 5

Before escalating therapy, always reconsider alternative causes of cough and assess medication compliance. 1

Diagnostic Confirmation During Treatment

• A therapeutic trial with prednisone 30 mg daily for 1-2 weeks can establish the diagnosis when initial testing is inconclusive, with cough improvement expected within 3 days to 2 weeks 1, 4, 5
• Non-invasive inflammatory markers (sputum eosinophils or fractional exhaled nitric oxide) can predict corticosteroid responsiveness, though their routine use in cough-specific asthma management has weak evidence 1, 2
• Bronchial challenge testing (methacholine) helps distinguish cough variant asthma from non-asthmatic eosinophilic bronchitis, which also responds to ICS but lacks airway hyperresponsiveness 1, 2

Critical Clinical Considerations

Common pitfall: Do not use beta-agonists alone, as cough variant asthma typically does not respond to bronchodilators without concurrent anti-inflammatory therapy. 1, 3

Important distinction: Non-asthmatic eosinophilic bronchitis presents identically with isolated chronic cough and eosinophilic inflammation but lacks airway hyperresponsiveness; it also responds to ICS as first-line treatment with the same stepwise escalation approach. 1

Long-term benefit: Inhaled corticosteroid treatment may prevent progression from cough variant asthma to typical asthma with wheezing and dyspnea, with studies showing only 5.7% progression in treated patients versus 30% in untreated patients over 3-4 years. 3

Particle size consideration: Recent evidence suggests matching ICS particle size to airway involvement patterns (assessed by impulse oscillometry) may optimize outcomes, though this requires specialized testing not widely available. 7

Treatment Duration and Monitoring

• Most patients require long-term maintenance therapy with ICS to prevent cough recurrence 4, 5
• At mean follow-up of 28 months, 80% of patients remained controlled on inhaled steroids alone, with only 20% requiring low-dose alternate-day oral steroids 4
• Complete remission without ongoing therapy occurs in a minority of patients 4
• Gastroesophageal reflux disease commonly coexists and should be considered if response to asthma therapy is incomplete 1, 2