Histopathological support of antagonism of allergen-induced mast cell mediator release in human skin by a beta-2-agonist.

The site of antagonistic action on allergen-induced early skin reactions by the beta 2-agonist terbutaline was studied by light microscopy in 10 atopic subjects. Pretreatment with 1 microgram terbutaline intradermally 5 min prior to challenge with horse dander allergen produced an approximate inhibition of 85 and 55% of flare and wheal responses respectively (P less than 0.001). Biopsy specimens obtained from skin sites injected with allergen alone showed a reduced number of remaining stainable mast cells as compared to sites injected with terbutaline prior to allergen (P less than 0.05, Sign test). The data support the concept of in vivo inhibition of the mast cell mediator release reaction in atopic skin by terbutaline.