Temporary localized hypertrichosis after henna pseudotattoo.

We report the case of a 5-year-old boy who had a temporary dragon-shaped henna pseudotattoo, reinforced 4 days later. Two weeks later, as the pseudotattoo began to disappear, hypertrichosis developed in the area corresponding to the previous psuedotattoo. Skin biopsy showed an increase in vellus hair follicles, with slight peripheral fibrosis. After 4 months, the hypertrichosis resolved spontaneously.