Roh D, et al. - Because segmental nevus depigmentosus and segmental vitiligo can be difficult to distinguish from one another, researchers have identified clinical clues that may be useful in differentiating these two diseases. For this investigation, 63 patients with segmental nevus depigmentosus and 149 patients with segmental vitiligo were enrolled. Trunk and cervical dermatomes in segmental nevus depigmentosus and face and trigeminal dermatomes in segmental vitiligo were the most frequently involved. According to findings, clinical differences were noted between patients with segmental nevus depigmentosus and those with segmental vitiligo. In differentiating segmental nevus depigmentosus and segmental vitiligo, distribution (site, distance to axis, dermatome), vertical width, margin of lesion and presence of poliosis may be useful.