Superiority of Nebulized Corticosteroids over Dry Powder Inhalers in Certain Patients with Cough Variant Asthma or Cough-Predominant Asthma

Background: The particle distribution might differ between nebulizer therapy and metered-dose inhaler (MDI) or dry powder inhaler (DPI) therapy because the particles repeatedly enter/re-enter the airways with the nebulizer. Inhaled corticosteroids (ICS) were administered with a nebulizer to assess the benefit of changes in the distribution of particles in patients with cough variant asthma (CVA) and cough-predominant asthma (CPA). Methods: Patients whose symptoms were not controlled by their current therapy were enrolled. In patients receiving high-dose ICS by MDI or DPI (ICS-MDI/DPI), steroid therapy was switched to 1,320 mu g/day of nebulized dexamethasone (1,600 mu g as dexamethasone sodium phosphate) (chronic steroid-independent group). In patients receiving systemic steroids regardless of their ICS-MDI/DPI therapy, nebulized dexamethasone was added and any concurrent ICS-MDI/DPI therapy was halted to detect a steroid-sparing effect (chronic steroid-dependent group). In patients with acute exacerbation of CVA or CPA and persistent symptoms despite systemic corticosteroids, nebulized dexamethasone was added to assess its effect (acute group). Results: Superior symptom control was achieved in 10 out of 12 steroid-independent patients, 3 out of 6 steroid-dependent patients, and all 7 acute patients. Conclusions: Delivery of ICS via a nebulizer has advantages over ICS-MDI/DPI in some patients with CVA or CPA.