The specific cause of this disease is not very clear and may be related to sunlight as well as seasonal changes and age. In addition, the white spots on the area may also be vitiligo, the specific cause of vitiligo is not very clear, mainly the melanocytes in the area can not effectively produce melanin, resulting in the appearance of white skin, but the boundary is clear, and the white is generally porcelain white. It is also possible that the area skin trauma or skin surface inflammation after the inflammation and trauma repair the formation of pigment loss spot, which is also possible.