Cutaneous reactive hyperaemia: racial differences induced by corticoid application

The postocclusive hyperaemic reaction before and after a single 1 h application of a potent corticoid (clobetasol 0.05% in ointment) was recorded by means of laser Doppler velocimetry in order to elucidate different racial responses in skin vasoconstriction. Fourteen young male subjects entered the study (eight Caucasians, six Blacks). Reactive hyperaemia was recorded after 4 min of occlusion of the forearm blood flow. The following parameters of the hyperaemic reaction were investigated: area under the curve response, peak response, rise of blood flow slope to peak and decay of blood flow slope after peak. Different responses were recorded in the Black subjects after the vasoconstrictive stimulus compared to the Caucasians, namely: decreased area under the curve response (P < 0.04); decreased peak response (P < 0.01); decreased decay slope after peak blood flow (P < 0.04). These data are consistent with a different reactivity of blood vessels in black skin and possibly not related to the transcutaneous penetration of the chemical compound.