The direct cause of white spots on the skin is melanin deficiency, which is a symptom caused by the disorder and decreases in melanin metabolism. The common causes of melanin deficiency are vitiligo, albinism, senile leukoplakia and other diseases.1. Vitiligo: The specific cause of vitiligo is unknown and may be related to autoimmunity, genetics, neurochemicals, etc., leading to the inhibition of tyrosinase system and melanocyte destruction and onset. The clinical manifestation is milky white or porcelain white pigment loss spot. It can be treated with proper supplementation of vitamin B, vitamin E, folic acid, calcium, and antioxidants. Stable vitiligo can be treated with skin grafting and combined with phototherapy to improve the efficacy; 2. Albinism: it is a hereditary disease, the symptoms can start from children and can be seen as pure white or pink spots. Daily attention should be paid to isolate ultraviolet light and reduce going out. There is no effective treatment for this disease; 3, senile leukoplakia: it is a kind of senile spot, the skin at the white spot is slightly depressed, mostly in the limb parts, and the face usually does not occur. This disease is usually a natural phenomenon of senile degeneration, without other discomfort, no special treatment is generally needed; 4, other: pityriasis simplex, pityriasis foliacea, post-inflammatory hypopigmentation, etc., can lead to local skin hypopigmentation and the formation of white spots; anemic nevus can be manifested as pale spots of different sizes due to defective vascular tissue or abnormal function; non-pigmented nevus occurs in children, and limited light white spots are visible at birth. The edges are jagged and last for life.