Linear and whorled nevoid hypermelanosis (also known as "Linear nevoid hyperpigmentation," "Progressive cribriform and zosteriform hyperpigmentation," "Reticulate and zosteriform hyperpigmentation," "Reticulate hyperpigmentation of Iijima and Naito and Uyeno," "Zebra-like hyperpigmentation in whorls and streaks," and "Zebra-line hyperpigmentation"[1]) is a disorder of pigmentation that develops within a few weeks of birth and progresses for one to two years before stabilizing.[2]: 549 There is linear and whorled hyperpigmentation following the lines of Blaschko without preceding bullae or verrucous lesions.[2]: 549 It is important to exclude other pigmentary disorders following the Blaschko lines before making a diagnosis of linear and whorled nevoid hypermelanosis. The differential diagnoses include incontinentia pigmenti, linear epidermal nevus, hypomelanosis of Ito and Goltz syndrome. Recently, a case of linear and whorled nevoid hypermelanosis was reported in a Malaysian Chinese girl.[3]
