Nevus of Ota is a blue hyperpigmentation that occurs on the face. It was first reported by Dr. M. T. Ota of Japan in 1939.

Nevus of Ota is caused by the entrapment of melanocytes in the upper third of the dermis. It is found on the face unilaterally and involves the first two branches of the trigeminal nerve. The sclera is involved in two-thirds of cases (causing an increased risk of glaucoma). It should not be confused with Mongolian spot

Mongolian spot

A Mongolian spot, also known as "Mongolian blue spot," "Congenital dermal melanocytosis," and "Dermal melanocytosis" is a benign, flat, congenital birthmark with wavy borders and irregular shape, discovered on and named after Mongolians by Erwin Bälz. It is also extremely prevalent among East...

, which is a birthmark caused by entrapment of melanocytes in the dermis but is located in the lumbosacral region. Women are nearly five times more likely to be affected than men, and it is rare among white people. Nevus of Ota may not be congenital, and may appear during puberty

Puberty

Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...

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Treatment

Q-switched laser has been used for treatment.

Hydroquinone preparations are also helpful in partially treating this defect.