Red small blood nevus, also called hemangioma, is formed gradually by the proliferation of vascular endothelial cells and the expansion of capillary ends. A small amount of vascular nevus can be found more or less in normal people, which is a normal phenomenon, and some people have more vascular nevi. The common reasons are as follows: 1. obesity: fat of overly obese people contains a lot of estrogen, which is an important factor leading to the increase of hemangioma; 2. drug factors: taking birth control pills can increase estrogen in the body, or the application of estrogen therapy during the treatment of certain diseases can also increase estrogen in the body; 3. trauma factors: local physical friction stimulated by trauma can also lead to hemangioma, and some cosmetics also contain estrogen; 3. Some cosmetics also contain estrogen; 4. Genetic factors: Some people have genetic tendency and family members are more likely to have angiogenic nevi. The disease is mainly treated by electrocautery, freezing and laser.