Birthmarks--discolorations on the skin--often occur at birth or in the first few months after birth. Many birthmarks disappear or fade within a few years after birth, while others remain permanently. Causes vary depending on the type of birthmark. Contrary to old wives' tales, birthmarks aren't caused by foods a mother eats or any other external factors, Nemours Foundation KidsHealth assures.
Hemangiomas
Hemangiomas, a collection of abnormal blood vessels, often appear at birth or within the first few weeks as a small red spot. Most hemangiomas affect the face, scalp or back of the neck, but they can appear anywhere. Hemangiomas often expand rapidly, becoming a reddened, spongy mass several inches in diameter and protruding slightly from the skin by the end of the first year.
Hemangiomas affect girls more than boys, Caucasian babies more than dark-skinned babies and premature infants more than full term. It's not known exactly why extra blood vessels grow, but certain proteins produced by the placenta may cause the abnormal growth, MayoClinic.com reports. Half of all hemangiomas fade by age 5 and nearly all disappear by age 10 without any treatment, the same source explains.
Mongolian Spots
Mongolian spots, which have nothing to do with being Asian, occur more often in darker-skin babies. Ninety percent of Native Americans and African Americans, 80 percent of Asians, 70 percent of Hispanics and 10 percent of Caucasian babies have at least one, reports pediatrician and columnist Alan Greene, M.D.
Mongolian spots, present at birth as brown, blue-black or slate-gray spots that range from pinhead size to several inches, consist of dense groups of melanocytes, cells that contain melanin, normal skin pigment. Deeper collections of melanocytes appear deeper blue, while those on the surface are more brown. Mongolian spots often fade by age 2 and disappear by age 5, Greene explains; less than 5 percent remain until adulthood.
Port-Wine Stains
Port-wine stains, which most often occur on the face but may occur in other locations, affect 3 in 1,000 infants. Port-wine stains, which are caused by swollen blood vessels beneath the skin, start out flat and pink and darken to deep red or purple as a child grows. People with certain syndromes such as Sturge-Weber syndrome are more likely to have port-wine stains.
Port-wine stains don't disappear or fade without treatment. Laser, freezing, surgery and radiation have been been used to treat port-wine stains, with laser being the most effective and the least damaging to the skin.
Congenital Melanocytic Nevi
Congenital melanocytic nevus, another term for a mole, occurs in 1 percent of infants, states DermNet NZ. Overgrowth of melanocytes, pigment-containing cells, causes congenital nevi, which range from small--1.5 cm--up to giant--over 20 cm. The moles often grow as the child grows and are difficult to remove without scarring. Giant congenital nevi pose a 5 percent risk of turning cancerous over a lifetime, DermNet NZ warns.
