Birthmarks are colored marks on the skin that are present at birth
or that develop shortly after birth, and may be brown, tan, black, blue or
blue-gray, pink, white, red, or purple. Some birthmarks appear on the surface
of the skin, some are raised above the surface of the skin, and some are
located under the skin.
Most birthmarks need no treatment. They often fade as a child grows
older. But some birthmarks may need treatment because of their location.
Experts do not know why some children have birthmarks and others do
not.