Acquired bilateral nevus of Ota-like macules (ABNOM), also known as Hori nevus, is one of the most commonly acquired dermal facial melanocytoses among people with dark skin, especially Asian women.

The goals of this article were to review published work on ABNOM; address controversies about pathogenesis and therapeutic approach; and inspire further study.

Articles in the literature related to the description of ABNOM were extracted and summarized.

Clinically, ABNOM occurs predominantly on the face of middle-aged women. Histologically, it is characterized by irregularly shaped, bipolar melanocytes dispersed through the mid to papillary dermis. Therapeutically, various pigment-targeting lasers have emerged as the major mode of treatment.

There is a notable absence of both biological insight into the cause of ABNOM and robust trials to effectively define a standardized therapy. The scattered reports in the literature preclude a more rigorous meta-analytical approach.

Although there have been many reports on ABNOM since 1984, the pathogenesis still remains unclear and controversial, and treatment of ABNOM is still challenging.