Birthmarks: Common Types, Causes, and Treatment

As parents welcome their newborn into the world, they may be surprised to discover their new bundle of joy has a birthmark. Of course, anything unexpected can understandably cause worry for parents, but birthmarks are generally harmless. Read on to learn more about the different types of birthmarks and if treatment is an option.

What is a birthmark?

A birthmark is any noticeable difference in an area of the skin present at birth or shortly after. Birthmarks can be any shape, flat or raised, and can be many colors. Some fade, while others are permanent.

What causes birthmarks?

Some birthmarks, such as nevus simplex, run in families. Others, such as dermal melanocytosis, are more common in certain ethnicities and skin tones. Hemangiomas often happen in babies born premature, at low birth weight, or in babies born as part of multiples like twins or triplets. Although some risk factors for birthmarks are known, the exact causes of birthmarks are not well understood. One thing is certain: they are unrelated to anything a mother did or didn't do.

Types of birthmarks

Birthmarks fall into two main categories: vascular or pigmented birthmarks. The American Academy of Pediatrics provides pictures of common birthmarks in their guide to baby birthmarks.

Vascular birthmarks

Vascular birthmarks are those that occur when blood vessels form improperly. The blood vessels grow too quickly or wide, making them more visible than usual.

Infantile hemangiomas

Hemangiomas occur when blood vessels grow too quickly near the skin's surface. Sometimes called “strawberry marks,” hemangiomas are a cluster of tangled blood vessels that typically look like a red, raised, bumpy area.

Not always present at birth, hemangiomas can also appear within the first days or weeks of life. They can start very tiny and flat, but always grow rapidly over the first months of life. Once they stop growing by about 6 to 12 months of life, they will start to shrink. Hemangiomas typically go away during the first years of childhood. Some will disappear as early as a year, and almost all will fade by ten years of age.

Nevus simplex

Caused by a small cluster of blood vessels directly beneath the skin, a nevus simplex has a salmon color or deep pink appearance. Nevus simplexes are also called salmon patches, macular stains, or stork bites. This birthmark is most common over the forehead, eyelids, and the back of the neck. When located on the face, they generally disappear by the age of 3 years, while those on the neck may always be visible.

Port wine stains

Port wine stains are caused by a collection of visible blood vessels under the skin. These markings may start pink, but change to a deep purple or red color that does not fade with time. If left untreated, the skin over port wine stains will change texture with time, and the affected skin will feel thickened.

Pigmented birthmarks

Melanocytes, the cells that cause pigment in our skin, are responsible for pigmented birthmarks.

Dermal melanocytosis

Commonly called Mongolian spots, dermal melanocytosis are large spots that appear bluish-grey. They most frequently appear on the lower back and buttocks, but can appear anywhere on the body. Mongolian spots mainly occur with darker skin tones and are most common in people of Asian descent. They almost always fade and disappear by 3–5 years of age.

Congenital nevi (moles)

Although moles, or congenital nevi, can appear at any stage of life, they can also be present at birth. Moles are usually tan or dark brown and can be raised or flat. If present at birth, moles generally are permanent, although a small percentage may disappear over time.

Café au lait spots

Café au lait spots are flat, darkened areas with well-defined borders. Their color can be like that of coffee with milk in fair skin tones, and appear dark brown or almost black in darker skin tones. Café au lait spots do not fade with time.

Are birthmarks unhealthy?

Most birthmarks are not a cause for concern. However, there are some situations when a dermatologist or other qualified healthcare provider should monitor birthmarks:

• Multiple hemangiomas. Sometimes multiple skin hemangiomas are associated with additional hemangiomas inside the body affecting internal organs.

• Hemangioma near the eye or lip. Hemangiomas that may impair vision or feeding may require treatment.

• More than 6 café au lait spots. Genetic conditions such as neurofibromatosis sometimes cause multiple café au lait spots.

• Moles. Moles present at birth can slightly increase the chance of melanoma. Parents and a dermatologist or healthcare provider should monitor moles for changes.

Should birthmarks be treated?

Most birthmarks do not require treatment for medical reasons. However, there are some exceptions.

Hemangiomas that become large, risk interfering with vision or the airway, or are prone to bleeding, may benefit from treatment. There are both oral and topical medications that are effective at shrinking hemangiomas.

Even if not needed medically, elective treatment options may be available for other birthmarks. For example, port wine stains are often treated with a laser to lighten the color and prevent thickened skin texture later in life. If large or very visible birthmarks cause distress to an individual, a dermatologist can discuss treatment options. Laser treatment, medications, topical treatments, or surgical removal may be options to lighten or remove birthmarks.

Many babies will have birthmarks at or shortly after birth. It is normal for parents to worry about birthmarks, but most are not a cause for concern. Talk to your baby's healthcare provider if your baby has a birthmark that is causing you concern.