A mole, technically known as a nevus, is a common, pigmented spot or growth on the skin. These growths form when melanocytes, the cells that produce the skin’s color, cluster together instead of spreading evenly throughout the skin. While most people have several moles, not all babies are born with them. Although a small percentage of infants have moles at birth, the majority of these growths develop later in childhood. Understanding the appearance and timing of these features helps parents monitor their child’s skin health effectively.
The Timing of Mole Appearance in Infants
The presence of moles in newborns is categorized by when they appear. Moles present at birth are uncommon, occurring in only about one to three percent of all newborns. These congenital moles may be larger and require specific monitoring by a healthcare provider.
The vast majority of moles seen throughout childhood are not present at birth but develop in the first few years of life. One study showed that while only 2.3% of infants had a mole at birth, this proportion jumped significantly to 65.2% by 12 months of age. By the time children reach two years old, almost all of them will have developed at least one mole.
The rate at which new moles develop tends to be highest in early childhood and slows down after age seven. Sun exposure is understood to play a role, with moles often appearing in areas that receive more sunlight, such as the upper limbs, head, and neck.
How Moles Differ from Common Baby Birthmarks
Many different types of spots and marks can appear on a baby’s skin that are not moles. Moles are generally uniform in appearance, ranging from tan to black, and can be flat or slightly raised. They are distinct from the more common vascular or other pigmented birthmarks that infants display.
One common pigmented birthmark is the Mongolian spot, which typically appears as a flat patch of bluish-gray color, sometimes mistaken for a bruise. These spots are most often found on the lower back or buttocks and are more prevalent in infants with darker skin tones. Unlike moles, Mongolian spots are a type of dermal melanocytosis, meaning the pigment cells are lodged deeper in the skin. They usually fade away completely before a child reaches school age.
Another frequent finding is the café-au-lait spot, named for its light brown, or “coffee with milk,” color. These spots are flat, uniformly colored, and can appear anywhere on the body, increasing in number as the child grows older. A single café-au-lait spot is usually harmless, but the presence of six or more spots larger than a pencil eraser warrants a medical evaluation, as it can be associated with a genetic condition like neurofibromatosis.
Infantile hemangiomas are vascular birthmarks made of concentrated blood vessels, not pigment cells. These often appear a few weeks after birth as a bright red, soft, raised lesion, sometimes called a “strawberry mark.” Hemangiomas grow rapidly during the first six to twelve months before beginning a slow process of shrinkage and eventual fading, which distinguishes their growth pattern from that of a mole.
When a Mole Requires Medical Attention
While most moles that appear on a baby or young child are benign, parents should consistently monitor any pigmented spot for changes. Any mole present at birth, especially if large, should be regularly examined by a pediatrician or dermatologist. The primary concern is detecting any unusual changes that could signal a problem, such as a very rare form of skin cancer.
Parents can use a simplified approach based on the well-known ABCDE guidelines to monitor their child’s moles. The most telling sign is Evolving, meaning any change over time. This includes new symptoms like a mole that begins to bleed, itch, or crust over. Regular skin checks during well-child visits allow the pediatrician to document and monitor moles, providing reassurance or recommending a specialist consultation if a spot appears concerning.
The ABCDE guidelines focus on looking for:
- Asymmetrical shape, where one half does not match the other.
- A poorly defined Border that appears ragged, notched, or blurred.
- Color variation, such as multiple shades of brown, black, red, or white.
- A large Diameter, typically bigger than a pencil eraser (about 6 millimeters).
- Evolving changes in size, shape, color, or elevation.