Small white spots on the skin can be caused by idiopathic pitting leukoplakia, vitiligo, anemia nevus and other factors. 1. idiopathic pitting white spots: idiopathic leukoplakia, also known as senile leukoplakia, usually occurs in the elderly population, often distributed in the limbs and chest and abdomen, most of them appear to be round or oval pitting white spots, long time after the occurrence of atrophy, the white spots are slightly lower than the surrounding normal skin. 2. vitiligo: vitiligo when the skin can appear small white spots like change, the skin lesions are round or irregular pigmentation spots, the surface is smooth, the border of the white spots is clearer, but also in the surrounding see pigmentation ring and other performance. 3. Anemic nevus: Anemic nevus is caused by congenital vascular function abnormality, and it can appear light white spots, usually with clear but irregular boundary, single or multiple, and often occurs on the trunk and chest and back and other parts of the body. When small white spots appear on the skin, you should consult a doctor in time, and under the guidance of specialists, you can actively take appropriate treatment to help relieve the uncomfortable symptoms as soon as possible.