Source:http://linkedlifedata.com/resource/umls/id/C0265974
MEDLINEPLUS: <p>Birthmarks are abnormalities of the skin that are present when a baby is born. There are two types of birthmarks. Vascular birthmarks are made up of blood vessels that haven't formed correctly. They are usually red. Two types of vascular birthmarks are hemangiomas and port-wine stains. <a href='http://www.nlm.nih.gov/medlineplus/skinpigmentationdisorders.html'>Pigmented</a> birthmarks are made of a cluster of pigment cells which cause color in skin. They can be many different colors, from tan to brown, gray to black, or even blue. <a href='http://www.nlm.nih.gov/medlineplus/moles.html'>Moles</a> can be birthmarks.</p><p>No one knows what causes many types of birthmarks, but some run in families. Most birthmarks are not serious, and some go away on their own. Your baby's doctor will look at the birthmark to see if it needs any treatment or if it should be watched. Pigmented birthmarks aren't usually treated, except for moles. Treatment for vascular birthmarks includes laser surgery. </p>