The skin vasoconstrictor assay does not correlate significantly to airway or systemic responsiveness to inhaled budesonide in asthmatic patients.

Objective: The responsiveness to inhaled corticosteroid varies among individual asthmatic patients. It is not known, however, whether the effects of corticosteroids on one bodily tissue reflect the response in another in a given individual. The aim was to a assess whether skin vasoconstrictor assay might predict airway and systemic tissue responsiveness to inhaled budesonide in patients with asthma.
Methods: Twenty-two patients with mild to moderate persistent asthma previously enrolled in a dose-response study assessing the effects of inhaled budesonide on airway bronchial challenge testing, exhaled nitric oxide and blood cortisol and eosinophil count were recalled for assessment of vasoconstrictor response to topical budesonide. The MacKenzie vasoconstrictor assay was performed by applying tenfold dilutions from 10(-2) g/ml to 10(-8) g/ml budesonide and visually assessing the degree of skin blanching after 18 h at each concentration.
Results: There was a significant overall dose-response effect for the degree of skin blanching at each concentration. There was no significant correlation between the effects on the skin and measures of anti-asthmatic efficacy or systemic effect after 3 weeks of 400 microg/day inhaled budesonide. There was a significant correlation with the overall dose-cutaneous response effect versus the overall dose-response effect with adenosine monophosphate (r=-0.53) but not methacholine bronchial challenge testing or serum cortisol.
Conclusion: It may not be possible to use the McKenzie vasoconstrictor assay to predict which patients are most or least susceptible to inhaled corticosteroids for anti-asthmatic efficacy or systemic adverse effects.