[Hypomelanosis guttata idiopathica].

A 37-year-old white female with dark complexion presented with progressive hypopigmented macules on the face and upper trunk. She was in good health and her family history was unremarkable. Histologic examination of the hypopigmented patches revealed reduced melanin within the basal layers of the epidermis. Using immunohistochemical and ultrastructural studies, the number of melanocytes appeared normal but signs of degeneration were evident and dendrites were shortened. The diagnosis of idiopathic guttate hypomelanosis was established. The clinical picture, etiology and treatment of this relatively common but often unrecognized skin disease is discussed.