Cutaneous immediate hypersensitivity in man: effects of systemically administered adrenergic drugs

In in vitro models of hypersensitivity, beta adrenergic drugs inhibit the antigen-induced release of histamine and other mediators from mast cells and basophils. Epinephrine, an agent with both beta and alpha adrenergic properties, is clinically useful for treating immediate hypersensitivity reactions. We examined the effects of intravenously administered adrenergic drugs on cutaneous wheal-and-flare reactions to antigens and histamine in 7 normal men. Both epinephrine and isoproterenol, a beta agonist, inhibited skin reactions produced by antigen or histamine. Phenylephrine, an alpha adrenergic agonist, produced no effect. These results suggest that epinephrine's inhibition of cutaneous immediate hypersensitivity in vivo is mediated by beta, rather than alpha, receptors. This inhibitory effect in vivo is probably not mediated solely in preventing allergic release of inflammatory mediators since the skin reactions to histamine were inhibited as well.