Dopamine inhibition of histamine-mediated cutaneous responses.

Several patients receiving dopamine for hypotension were skin tested for possible penicillin sensitivity. Not only were the penicillin skin tests negative but also the histamine control. On the possibility that dopamine might affect cutaneous histamine responses, we examined the effect of dopamine on histamine, antigen, morphine, and compound 48/80 skin responses. Both intradermal and intravenous dopamine selectively inhibited histamine but not antigen, morphine, or compound 48/80 skin responses, and the inhibition was in a dose-related fashion. This observation indicates that histamine should not be used to demonstrate dermal reactivity in patients receiving dopamine. The results of this study also suggest that histamine may not be the sole mast cell-derived mediator involved in the wheal-and-flare reaction characteristic of immediate-type skin tests since dopamine did not affect skin reactions caused by endogenous mast cell degranulation. Finally, the possible use of dopaminergic drugs in diseases with histamine-associated symptoms is discussed.