What is the recommended initial treatment for cough variant asthma?

Cough Variant Asthma: Initial Treatment

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

First-Line Therapy

• Start with low to medium dose ICS (equivalent to beclomethasone 200-800 μg daily) administered twice daily 2
• Use proper inhaler technique with large volume spacers for metered-dose inhalers to optimize drug delivery 2
• Beta-agonists should be added in combination with ICS rather than used as monotherapy, as LABA monotherapy increases the risk of serious asthma-related events 3, 4
• The evidence supporting ICS as first-line therapy is graded 1B by the American College of Chest Physicians, reflecting very strong evidence from the broader asthma treatment literature 1

Treatment Duration and Response Assessment

• Continue initial ICS therapy for 4-8 weeks while monitoring cough symptoms 3
• Cough control should be expected within 1-2 weeks if due to eosinophilic airway inflammation 2
• If no response occurs after 2 weeks of treatment equivalent to prednisolone 30 mg/day, cough is unlikely due to eosinophilic airway inflammation and alternative diagnoses should be considered 1, 2

Stepwise Escalation for Incomplete Response

If cough persists after initial ICS therapy, follow this sequential approach:

1. Increase the ICS dose up to a daily equivalent of 2000 μg beclomethasone 2, 3

2. Add a leukotriene receptor antagonist (such as montelukast 10 mg daily) after reconsidering alternative causes of cough 1, 2, 3

   • Specific evidence supports this combination in cough variant asthma, with one study showing 75.7% improvement in cough frequency by 4 weeks 5
   • Leukotriene inhibitors modulate the inflammatory environment around sensory cough receptors 3

3. Consider short-course oral corticosteroids (prednisolone 30 mg daily for 1-2 weeks) only after the above steps fail, then transition back to inhaled therapy 1, 2, 3

Diagnostic Confirmation

• Bronchial challenge testing (methacholine inhalation test) demonstrates airway hyperresponsiveness and distinguishes cough variant asthma from non-asthmatic eosinophilic bronchitis 2, 3
• Non-invasive inflammatory markers (sputum eosinophil counts or fractional exhaled nitric oxide) predict corticosteroid responsiveness, though evidence for their use specifically in cough variant asthma is weak (Grade 2B) 1, 2
• A diagnostic trial of oral prednisolone 30 mg daily for 2 weeks can establish the diagnosis when testing is unavailable, as no currently available tests reliably exclude corticosteroid-responsive cough 2

Critical Pitfalls to Avoid

• Do not use long-acting beta-agonists at step 3 in cough variant asthma, as there is no evidence supporting their use at this stage 1, 2
• Do not prescribe newer non-sedating antihistamines for asthma cough management, as they are completely ineffective 3
• Do not 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 3
• In patients with apparently corticosteroid-resistant cough variant asthma, reconsider alternative diagnoses including gastroesophageal reflux disease (which commonly coexists), ACE inhibitor use, and smoking 1, 2

Long-Term Management Considerations

• Maintenance therapy with ICS is recommended even after cough resolution, as 30-40% of patients with cough variant asthma progress to classic asthma if inadequately treated 6, 7, 8
• Discontinuation of anti-inflammatory therapy causes worsening of disease with return to baseline levels of cough, pulmonary function decline, and eosinophilic airway inflammation 6
• Combination therapy with salmeterol/fluticasone provides superior improvements in cough symptoms, pulmonary function, and airway inflammation compared to salmeterol alone 6