Water immersion and EMLA cause similar digit skin wrinkling and vasoconstriction

Water immersion skin wrinkling tests limb sympathetic vasoconstrictor function. We have recently shown that water immersion wrinkling is accompanied by digit vasoconstriction and postulated that vasoconstriction is the main underlying mechanism. To test this further, we applied vasoconstrictive cream (EMLA) to the distal digit and compared the degree of skin wrinkling and digit blood flow reduction with those after water immersion. In 25 healthy volunteers (6 male, 19 female; mean age, 35 yr) subjected to EMLA and water immersion, both clinical wrinkling scores and reduction in digit blood flow (mean of 2.01 and 2.29 cm/s, respectively) were nearly identical. Control using aqueous cream resulted in minimal skin wrinkling and nonsignificant reduction in digit artery flow (P = 0.170). These data further support that water immersion skin wrinkling is mediated by vasoconstriction. The EMLA cream patch test may develop into a useful screening test for hand sympathetic vasoconstrictor function.