Birthmarks

What are birthmarks?

Birthmarks are areas of discolored and/or raised skin that are apparent when your baby is born or within a few weeks of birth. Birthmarks are composed of pigment cells or blood vessels. About 10 percent of babies have a vascular birthmark.

Most birthmarks are harmless, but there are a few that can require treatment based on where they're located and whether they’re growing. It’s a good idea to have your pediatrician check out your baby’s birthmark just in case.

What are the different types of birthmarks?

There are two main types of birthmarks.

Vascular birthmarks 

Vascular birthmarks are caused by incorrectly formed blood vessels in your child’s skin. Examples include:

  • Infantile hemangiomas: the most common vascular birthmark, it usually appears within one to two weeks of birth. Infantile hemangiomas grow rapidly during the first few months of life and then begin to shrink and fade when your baby is around 1 year old. Most of the time, they cause no problems and go away on their own.
  • capillary malformation, or "port-wine stain": flat, red-pink stain that usually appears on your child's face or neck. It’s a mostly cosmetic problem that usually doesn’t need any treatment at all. But if it doesn’t go away and is in a prominent location, you may want to consider pulsed dye laser therapy for your child.
  • nevus flammeus pinkish birthmarks that appear on your child’s forehead, eyelids or neck. They usually fade significantly by the time your child is 2 years old. Nevus flammeus birthmarks don’t require any treatment.

Pigmented birthmarks

Pigmented birthmarks are caused by an overproduction of pigmentation. Examples include:

  • Café au lait spot: flat, tan spots that can appear anywhere on your child’s body. They’re completely harmless, but if your baby has more than five of them, you should have her screened for neurofibromatosis or other genetic conditions.
  • Slate gray nevus (“Mongolian blue spot”): large, blue-gray birthmarks that resemble bruises and commonly appear on the lower back. They’re completely harmless and usually fade without any treatment.
  • Congenital nevus (“mole”): raised brown spots which are extremely common and can appear anywhere on your child’s body. If your child has a very large mole, you should have it checked out by a pediatrician, as it could increase her risk for skin cancer.

How we care for birthmarks

Should we need to treat your child, you’re in the right place. Boston Children’s is home to the world’s largest and most experienced Vascular Anomalies Center. When doctors anywhere in the world have questions about a child’s birthmark and how to treat it, they usually call us.

Our doctors have seen and treated many kids with many different kinds of birthmarks—which means that if your child needs treatment, he'll get expert care from experienced physicians.