EDN1 and freckles: The intensity of epidermal expression of ET-1 was increased in the lesional skin of Riehl’s melanosis (H score, mean ± SD = 163.48 ± 15.07) compared to normal-appearing perilesional skin (H score, mean ± SD = 111.20 ± 7.76; p = 0.001) and healthy controls (H score, mean ± SD = 66.60 ± 10.86; p = 0.0001; Figure 6).