Physiologic hyperpigmentation on darker skin

Many, even common, normal variations and nuances of skin of color are less frequently described or often misinterpreted as pathological. Recognizing these physiologic changes is gaining relevance in our increasingly diverse patient population and enables the physician to encourage the acceptance by the patients as well as to manage our resources wisely. Therefore, we explain common hyperpigmentation on dark skin such as demarcation lines, mucosal hyperpigmentation, melanonychia striata, and circumscribed dermal melanocytosis. The aim of this article is to facilitate the classification of these phenomena in clinical practice.