3 Things Parents Need To Know About Congenital Nevi

Posted on: 5 April 2016

Congenital nevi, also called birthmarks, are patches on the skin that affect a reported 1.3% of newborns. These patches can be various shades of brown and may have irregular or hairy surfaces. Here are three things parents need to know about congenital nevi.

What causes congenital nevi?

The cause of congenital nevi is still unclear. One theory is that these patches have a genetic link. Children that carry the MC1R genotype—a genotype that is associated with red hair—have been shown to have a higher risk of developing these patches. This doesn't explain every birthmark, though, because dark-haired and dark-skinned infants also get them.

Another theory is that environmental factors lead to a mutation in the neuroectoderm, one of the germ layers that makes up a developing embryo. This mutation is thought to affect the way the melanin-producing cells develop, which can lead to dark patches on the skin.

Are congenital nevi serious?

If your child's nevus is small, it may not pose any concerns for them, especially if it's located in a hard-to-see area. Larger patches, or patches that are on the face, neck or other visible areas, may make affected children feel uncomfortable about the appearance of their skin. Very irregular or hairy patches may lead to teasing or bullying at school.

Large congenital nevi may pose serious medical concerns in addition to these cosmetic concerns. According to the Textbook of Dermatologic Surgery, between 5% and 20% of these large nevi become malignant later in life. This means that the birthmark turns into cancer when the child gets older.

Can congenital nevi be treated?

If your child's nevus is small, and they aren't annoyed by its appearance, there's no reason to treat it. If the nevus is large, their dermatologist will recommend removing it. Removal of these large nevi is done for two reasons: to improve the look of the skin and to help prevent malignant transformation.

Small nevi can be surgically excised (cut away), and the wound can be stitched shut. This might leave a scar. Large nevi can't be stitched shut, so once they're excised, the wound will need to be repaired with skin grafts. Multiple surgical procedures may be necessary for very large nevi. Your child's dermatologist will let you know how many procedures will be needed to remove their nevus.

If your child has a large birthmark, or a small birthmark that bothers them, take them to a dermatologist, such as those at Heibel Dermatology, for treatment.