Children with dark neck may be related to genetic factors, sun exposure, obesity and so on. 1. Genetic factors: If the parents’ skin is darker, the child’s skin will also be darker under the genetic factors, and may feel darker neck. 2. Sun exposure: children go out to play without good sunscreen, under the action of ultraviolet rays, the child’s neck will be tanned by the sun. 3. Obesity: overweight obese children, may be combined with acanthosis nigricans, may cause the phenomenon of children’s neck black. Children’s neck black may also have other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor’s treatment.