Moles, also called “melanocytic nevi,” are common in newborns and infants (about 1%).

If they are seen at birth or develop during the first one-two years of life, they are called congenital melanocytic nevi. While most of these moles are small, some may be very large. Most of these will grow as your child grows.

Melanocytic nevi usually look like light to dark brown spots on the skin. In children with very light or fair skin, they may appear more pink or red in color. They may have hair growing in them, a bumpy texture, or slowly get darker in color; such changes are generally normal.

Most congenital melanocytic nevi do not need treatment. However, all moles carry a very small risk for the development of melanoma, a type of skin cancer. The development of melanoma within a congenital melanocytic nevus is very rare.

However, children with a large congenital melanocytic nevus are at a higher risk for melanoma and for another condition called “neurocutaneous melanosis.” In neurocutaneous melanosis, there are too many pigment cells (called melanocytes − meh-lan-uh-site) in the brain and / or spinal cord. This can lead to seizures, developmental delays, or other neurological issues. Your doctor may order an MRI (imaging study) to look for these pigment cells.

Congenital melanocytic nevi do not go away with time. Some congenital melanocytic nevi may get lighter in color over the first few years of life.

Cause

All moles, including those that are congenital, are made of “melanocytes.” These are the cells that give skin its color (pigment). These cells are present in all skin types and colors, in varying degrees. In congenital melanocytic nevi, there are more of these cells, which makes that skin a darker color. It is not known what causes these to form, but a genetic cause is suspected.

Symptoms

There are usually no symptoms with congenital melanocytic nevi. Sometimes the larger ones may itch.

If pain, severe or persistent itching, bleeding, or crusting develop, see your child’s doctor.

Treatment

The majority of congenital melanocytic nevi do not need treatment.

Check the mole(s) each month. Watch for any changes in the way the mole(s) look. It may help to take a photo of the mole(s) with your smartphone or digital camera so you can tell if there have been any changes.

If there are any changes, such as areas of bleeding or crusting, new bumpy areas, areas that change color, new pain or itch, change in shape or rapid change in size, have your child see your doctor. Your doctor may suggest that a sampling or skin biopsy be done. This is usually done in an office and takes no more than a few minutes. For some congenital nevi, removal may be recommended. This may require general anesthesia in younger children or in any child with fear or anxiety about the procedure.

There is the small risk of melanoma developing with a congenital melanocytic nevus, so removing the mole may be an option. This may be also recommended if the nevus is:

• In an area that will be difficult to watch, such as the scalp or buttocks
• In a child with extreme anxiety or concern about the appearance of the congenital melanocytic nevus
• Very unusual in appearance

Removing a mole requires surgery. Although removing the mole will greatly reduce the chance of melanoma, it will leave a scar. This is to be considered when deciding whether or not to remove it. There are no lasers or other treatments that can be safely used to remove melanocytic nevi.

When to Call the Doctor

Call your doctor if any of the following changes develop with the congenital melanocytic nevus:

• Change in color
• Change in shape
• Rapid increase in size
• Itching or pain
• Bleeding or crusting
• New raised or bumpy areas