What is the initial treatment for cough variant asthma?

Initial Treatment for Cough Variant Asthma

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

Diagnostic Confirmation Before Treatment

• Demonstrate airway hyperresponsiveness through bronchial challenge testing (methacholine inhalation test) to distinguish cough variant asthma from other causes of chronic cough 2, 1
• Tests of airway responsiveness are more sensitive and specific than bronchodilator reversibility studies when spirometry is normal or near-normal (FEV1 >70% predicted) 2
• Consider measuring non-invasive inflammatory markers such as sputum eosinophil counts or fractional exhaled nitric oxide (FENO) to assess eosinophilic inflammation and predict corticosteroid responsiveness 1

Initial Treatment Regimen

Start with low to medium dose inhaled corticosteroids (equivalent to beclomethasone 200-800 μg daily), as higher starting doses provide no additional clinical benefit 1

• Administer twice-daily dosing with proper inhaler technique using large volume spacers with metered-dose inhalers to optimize drug delivery 1
• Dry powder inhalers are acceptable first-line alternatives due to ease of use 1
• Treatment duration should be 4-8 weeks initially while monitoring cough symptoms 1

Alternative Diagnostic-Therapeutic Approach

If diagnostic testing is unavailable or impractical, a trial of oral prednisolone 30 mg daily for 2 weeks can establish the diagnosis 2. This approach is particularly useful because:

• Cough will be controlled within 1-2 weeks if due to eosinophilic airway inflammation 2, 3
• Nine out of ten patients report significant improvement within 3 days 3
• If no response occurs after 2 weeks, an alternative diagnosis should be considered 2
• Following diagnostic confirmation, transition to inhaled corticosteroids for long-term management 4, 3

Stepwise Escalation for Inadequate Response

If cough persists after initial ICS therapy:

1. Increase the ICS dose up to a daily equivalent of 2000 μg beclomethasone 1
2. Add a leukotriene receptor antagonist (such as montelukast) as there is specific evidence supporting this combination in cough variant asthma 2, 1
3. Consider short-course oral corticosteroids only after the above steps fail 2

Critical Management Points

Do not use long-acting beta-agonists (LABAs) at step 3 in cough variant asthma, as there is no evidence supporting their use at this stage 2

• Management should otherwise follow national asthma guidelines 2
• Inhaled corticosteroids are effective for long-term control, with 90% of patients experiencing complete cough relief 5
• ICS not only relieve cough but also decrease bronchial hyperresponsiveness, reducing the risk of progression to classic asthma 5

Important Differential Consideration

Eosinophilic bronchitis (characterized by eosinophilic inflammation without airway hyperresponsiveness) also responds to ICS as first-line treatment with similar stepwise escalation 2, 1

• A negative bronchial hyperresponsiveness test excludes asthma but does not rule out steroid-responsive cough 2
• The presence of non-asthmatic corticosteroid-responsive cough syndromes emphasizes the importance of a trial of corticosteroids in all patients with chronic cough, regardless of airway hyperresponsiveness test results 2

Common Pitfall to Avoid

Gastroesophageal reflux disease commonly coexists with cough variant asthma and should be considered as a contributing factor 1. However, the primary treatment remains inhaled corticosteroids, not antireflux therapy, for cough variant asthma itself.