“…Therefore, the assessment of erythema in skin irritation has been widely investigated, either by visual assessment [28,37,41,59,60] or by quantitative methods such as tristimulus reflectance colorimetry (a* value) [20,50,51,52], reflectance spectrophotometry (erythema index) [38,53,59] or laser Doppler flowmetry (cutaneous blood flow) [20,41,48,50,51,53,61]. Increased vascular reactivity has been emphasized in the literature as a key player in sensitive skin pathophysiology.…”