Generally, children’s dark skin is not necessarily caused by a deficiency, because the causes of dark skin in children are very complex. The first is the lack of trace elements and vitamins, in children’s bodies lack of trace elements zinc and vitamins, often appear dark skin, you can test the body’s trace elements and vitamin levels to further confirm the diagnosis, if the zinc deficiency, you can give children timely supplementation of zinc gluconate. Secondly, if the child’s parents have darker skin, the child’s skin will be darker due to genetic factors, and also due to excessive sun exposure.