What exactly is a birthmark?

It's common for babies to have birthmarks at birth. Some of these marks may show up during the first few weeks. Birthmarks can appear in colors like red, pink, brown, tan, or blue. There’s no way to prevent them, and they aren’t inherited. Little is understood about their formation. Most are harmless and fade during early childhood. However, certain birthmarks can be more noticeable, leading to cosmetic concerns or, in rare cases, may be linked to cancer.

Birthmarks fall into two main categories: pigmented and red.

Red birthmarks can vary from small, pink spots to large, deep red patches. These marks are caused by blood vessels close to the skin’s surface and are also referred to as vascular birthmarks. There are two main types of vascular birthmarks: macular and hemangioma.

Macular

Macular birthmarks, sometimes called stork bites or angel's kisses, are extremely common in newborns. They occur due to visible capillaries (tiny blood vessels) beneath the skin. These delicate pink marks often appear on the forehead, eyelids, and back of the neck. They do not require any treatment and typically fade as the child grows.

Hemangiomas

Hemangiomas, often referred to as strawberry birthmarks, are also quite frequent. Most are small and harmless. Their bright red color and slightly raised texture are due to a cluster of blood vessels packed closely together near the skin’s surface. They generally appear around the face, neck, scalp, or chest, and are more commonly seen in females. Nearly all strawberry birthmarks disappear by the time the child reaches 9 years old.

Larger hemangiomas are referred to as cavernous hemangiomas. These appear as a red or blue tissue mass filled with blood. Some of these lesions may fade as the child grows.

The birthmark often called a port-wine stain is a flat hemangioma or nevus flammeus. It occurs in 3 out of every 1,000 infants. Port-wine stains are purplish discolorations caused by dilated blood capillaries. These stains typically appear on the face and are usually permanent. While most birthmarks don’t require medical treatment, large port-wine stains may. Treatment options include cryotherapy (freezing), surgery, surgical removal, or laser surgery, in addition to cosmetic concealing products.

Pigmented

Pigmented birthmarks are areas on the skin where the color differs from the surrounding skin.

Often referred to as café-au-lait spots (since they usually appear as light tan marks), these are typical birthmarks and generally do not signal any other issues. However, if multiple café-au-lait spots are larger than an American quarter, they could indicate neurofibromatosis—a genetic disorder causing abnormal nerve tissue growth—and should be assessed by a doctor.

Occasionally, moles known as nevi appear after birth and are harmless. However, nevi that are present at birth could suggest a higher risk of skin cancer (melanoma), particularly if the moles are very large. This type of birthmark should be monitored over time by a healthcare professional.

Children with darker skin tones may have a birthmark called Mongolian spots. These bluish marks are typically found on the lower back or buttocks and can resemble (and are sometimes mistaken for) bruises. They generally fade as the child grows.