Differential vasodilatory responses to local thermal stimuli in facial, glabrous and hairy skin

Abstract

Local heating of the cutaneous vasculature traditionally produces a biphasic vasodilatory response related to axon reflex and nitric oxide mechanisms, respectively. This study tested skin blood flow (% of maximum cutaneous vascular conductance; %CVC) responses of 22 healthy subjects to local heating (42°C for 45 min) in the forehead (facial skin that does not often flush), cheek (facial skin that actively flushes), forearm (control hairy skin), and palm (control glabrous skin) to gain insight into facial flushing disorders. Baseline flow at 32°C was higher in the palm (65±11) compared to the forehead and cheek (15±1 and 17±2) and compared to the forearm (7±2%CVC; P<0.05). Palm skin did not demonstrate a biphasic local heating response; 1st peak was 20±9% greater than the 2nd peak and the nadir returned to baseline values (P>0.05). No differences were observed in the 1st peak between the forehead, cheek, and forearm (85±3, 92±2, and 91±6%CVC). In the check, nadirs were not observed in most subjects and nadir values (82±3) were greater than both the forehead and the cheek (69±3 and 73±4%CVC; P<0.05). These data suggest differing local regulation of facial and glabrous skin compared to hairy skin.