Facial skin blood flow responses to irritant stimuli in the oral cavity

To investigate whether capsaicin and menthol stimuli elicit characteristic responses in facial skin blood flow (SkBF), we observed the facial SkBF response to low and high concentrations of capsaicin and menthol stimuli of 1-ml solution applied to the oral cavity for 20 s in 17 healthy subjects. High concentration of capsaicin significantly increased the SkBF in all of the facial areas monitored. High concentration of menthol stimulus significantly decreased SkBF in the nose and increased that in the eyelid, and upper and lower lips. These results demonstrated that capsaicin and menthol stimuli in the oral cavity elicit characteristic responses in facial SkBF.