A birthmark is a colored mark on or under the skin that has been present since birth or shortly after, usually within the first month. They can occur anywhere on the skin. Birthmarks vary in size and shape, and can be blue, black, tan, brown, pink, red, purple, or white. Some are smooth and some are raised and rough. Moles can be birthmarks.
Almost all birthmarks are painless and harmless. However, to be safe, it’s important to have a doctor check birthmarks, especially if there are rapid changes in appearance.
Birthmarks are categorized into two main groups: Those that appear as patches of brown skin (pigmented lesions) and those that appear as patches of red skin (vascular lesions). Pigmented 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. Two types of vascular birthmarks are hemangiomas and port-wine stains. They are caused by the presence of abnormal blood vessels that are bunched together and do not grow normally.