Nevus oligemicus. A variant of nevus anemicus

A man had a long history of a persistent, fixed area of livid erythema on the trunk. The distribution of hair, sweat, and sensation were normal as were the histologic findings in the affected skin. The involved area had a decreased total skin blood flow and a lower surface temperature compared with surrounding uninvolved skin, but showed normal responses to vasoconstrictor and vasodilator stimuli. Incomplete sympathetic blockade partially abolished the erythema. We suggest that the appearance of the nevus is caused by increased vasoconstrictor tone in the thermoregulatory vessels of the involved skin, leading to relative stasis in the superficial "nutritional" vasculature. This would seem to be a new example of a "pharmacological nevus" showing similarities to and differences from nevus anemicus.