To determine whether it is vitiligo or pityriasis alba, you can differentiate based on clinical manifestations as well as laboratory findings. 1.Clinical manifestations: (1) Vitiligo, as an acquired pigment deficiency skin and mucous membrane disease, is mainly manifested in the clinic as scattered white patches appearing on the surface of the skin, with a smooth skin surface, and the hair in the middle of the white patches can be white. (2) white furfur, called simple furfura, for the face of limited hypopigmented spots, rather than loss of spots, the edge of the lesion border is not clear, the surface is often fine phosphorus flakes. 2. laboratory findings: (1) Vitiligo: Vitiligo progression stage can skin lesions for white fluorescence, border is not clear; into the stable stage can be presented as a bright blue-white fluorescence, border is clear. (2) Furfura simplex: hypopigmented spots can be found when using Wood’s lamp, but there is no fluorescence. Due to the existence of certain differences in clinical manifestations, the specific circumstances need to ask the doctor for a face-to-face consultation.