A congenital hairy nevus is a darkly-colored, pigmented, often hairy patch of skin, also known as a mole, that is present at birth or develops within the first year of life. These moles are frequently found on the trunk or limbs, although they can appear anywhere on the body.

Characterized by size, a giant congenital nevus is one that grows with the child and is larger than 40 centimeters once it stops growing. In rare cases, giant nevi can be associated with a condition known as neurocutaneous melanocytosis, which produces excess pigment cells in the brain or spinal cord, leading to neurological symptoms. While many small congenital nevi are benign, larger ones can develop into melanoma (skin cancer).

Congenital nevi are thought to be caused by a genetic mutation that leads to a localized increase in melanocytes, the skin cells that produce melanin and give color to the skin. The condition may occur with the presence of other nevi.


Congenital nevi can be many colors and may reflect the child’s normal skin color. Most congenital nevi are a shade of brown. Long, dark or thick hair may be present in the nevus when it first appears or can develop over time.


Diagnosing congenital nevi can be done at birth through a physical exam. The size of the nevus will determine the treatment plan.


Congenital moles need to be monitored, and surgical removal is an option for moles that may lead to cancer, as well as those whose appearance may cause distress for your child due to location or size. Moles that change over time may be removed to prevent skin cancer, and surgical excision—a simple procedure—is the typical process.

Depending on the size of the nevus, surgical excision may be done in stages so the doctor can implement tissue expanders that promote the growth of extra, healthy skin to be used for implants after removal of the nevus. Dermatologists and plastic surgeons are part of our team of specialists at the North Carolina Cleft and Craniofacial Center, and they will provide your child with comprehensive care, from diagnosis to excision, recovery and follow-up.