Pruritic Acquired Nevus of Ota

Nevus of Ota is a unilateral, asymptomatic cutaneous and mucosal hyperpigmentation of the face that is congenital or may appear during childhood. We present a case of symptomatic acquired nevus of Ota in an adult, associated with intense pruritus, not described in the literature so far. A 32-yearold woman presented with brownish mottled macules which appeared on her face progressively over 8 days, following the distribution of the first and second divisions of the left trigeminal nerve and partially covering the iris and sclera of the left eye. She reported an intense pruritus in this area. We performed a biopsy on the left forehead, which confirmed the diagnosis of nevus of Ota. Specific stains and immunohistochemistry revealed increased numbers of mast cells. Ophthalmological tests showed acute acquired melanocytosis of the left iris and sclera. The origin of the nevus is still unclear. Several hypotheses suggest a reactivation of melanocytes during their migration from the neural crest. The pruritus reported in our patient may be explained by the increased