First described by Sutton in 1916 as "leukoderma acquisita centrifugum", a halo nevus is a common benign skin lesion that represents a melanocytic nevus surrounded by a white halo of depigmented skin. It is most commonly seen in adolescence, but can be observed at any age. Over a period of months to years, the halo nevus gradually involutes and disappears, often leaving a residual white patch. Halo nevi are usually single but may be multiple. Halo nevi can occur almost anywhere on the body, but most often appear on the trunk, especially the back. The exact etiology of halo nevi remains unknown but they are believed to be due to an immune response against melanocytes. Halo nevi are only of cosmetic concern and no treament is usually required.