Probably most people have birthmarks on their bodies, which are actually a kind of abnormal pigmentation, hypopigmentation and vascular abnormalities on the skin, etc. Most of them do not have obvious itching, pain and other conscious symptoms. It is a lesion caused by a complex combination of internal and external factors during embryonic development. It can be detected at birth or can appear shortly after birth. The occurrence is related to genetic factors as well as the diet and emotions of the pregnant woman. Some birthmarks may fade away slowly with time, such as the bright red nevus and Mongolian spot. However, most of them do not fade away on their own and sometimes they may be carried for life. Most birthmarks are not harmful to the body and most of them do not need to be treated. If you want to remove it, you can use laser or surgical methods.