Birthmarks generally result from an overgrowth of a structure that is normally present in the skin. For example, an overgrowth of blood vessels produces vascular birthmarks or haemangiomas; an overgrowth of pigment cells produces congenital naevi or moles. There are a number myths and superstitions about birthmarks.

What is the reason for birthmarks?

Causes of birthmarks

The occurrence of birthmarks may be inherited. Some marks may be similar to marks on other family members, but most are not. Red birthmarks are caused by an overgrowth of blood vessels. Blue or brown birthmarks are caused by pigment cells (melanocytes).

Are you born with birthmarks or do they develop?

Birthmarks appear when a baby is born or soon after birth. They are called birthmarks because they appear at or close to birth. If you see a mark on your skin that wasn't there before, it's most likely a mole and not a birthmark.