Nevi, commonly known as moles, are growths on the skin formed by clusters of pigment cells called melanocytes. These spots are an extremely common feature, with the vast majority developing during childhood and adolescence. Moles are overwhelmingly benign in children. The occurrence of melanoma, the most serious form of skin cancer, is exceptionally rare in the pediatric population. For children under the age of 10, the incidence rate is fewer than two cases per million. Learning the characteristics of a typical mole is the first step in monitoring skin health.
Characteristics of Typical Moles in Childhood
A normal mole in a child typically presents as a small, uniform spot that is round or oval in shape. These benign growths usually display a single, consistent color, such as a shade of tan, light brown, or dark brown throughout the lesion. The borders of a typical mole are well-defined, smooth, and regular, contrasting with more concerning irregular edges.
Moles often begin to appear after a baby is six months old, and new ones will continue to form throughout childhood and puberty. It is entirely normal for a child to develop between 10 and 40 moles by the time they reach adulthood. A common mole is generally small, usually measuring less than 6 millimeters, which is roughly the diameter of a pencil eraser.
A normal mole will grow symmetrically and proportionally as the child grows. While a mole may naturally thicken, darken, or lighten over time, especially during hormonal changes like puberty, the color within the spot should remain uniform. A helpful observation is the “signature nevus” concept, where most of a child’s moles look similar to one another, establishing a pattern of what is normal for that individual.
Some normal variants may look unusual but are not causes for alarm, such as two-toned “eclipse” moles often found on the scalp. Raised or dome-shaped moles are also common and do not automatically suggest malignancy. The key characteristic of a typical mole is its stability, maintaining a similar appearance over long periods, even as the child’s body grows around it.
Key Warning Signs and Changes to Monitor
The most important factor in determining a worrisome mole in a child is change over time, often referred to as the ‘E’ for Evolution. While the standard ABCDE criteria are generally used for adults, they must be applied carefully to children, with the focus on any mole that is changing quickly or looks distinctly different from the rest. Rapid changes in size, shape, color, or height are the primary signals that a mole needs professional evaluation.
The ABCDE Framework
The ABCDE rule provides a framework for monitoring moles, though the ‘E’ for Evolution is the strongest indicator of concern in pediatrics.
- A is for Asymmetry, meaning one half of the mole does not match the other.
- B stands for Border irregularity, where the edges are blurred, notched, or scalloped.
- C is for Color variation, which includes multiple colors or the appearance of red, white, or blue areas within the mole.
- D, or Diameter, refers to moles larger than 6 millimeters, though size alone is not definitive if the mole has been stable.
- E for Evolving, encompasses any noticeable change, including changes in size, shape, color, height, or texture (such as scaling, crusting, or the development of a non-healing sore).
The concept of the “ugly duckling sign” is highly relevant, referring to a mole that looks markedly different from the child’s other moles. Other immediate red flags signal a change in the mole’s biological state. A mole that begins to bleed spontaneously without injury warrants a checkup. Persistent itching or tenderness not explained by common irritations also falls into the category of concerning changes.
Some benign childhood moles, such as a Spitz nevus, can naturally appear atypical, often presenting as a raised, dome-shaped, pink, or reddish-brown spot. Because a Spitz nevus can visually mimic melanoma, any mole with these features, or one with a jagged border or multiple colors, should still be examined by a specialist for proper diagnosis.
When to Seek Immediate Medical Attention
If a mole begins to display any of the signs of rapid change or concerning symptoms, a parent should schedule an appointment with a pediatrician or dermatologist. An immediate call is warranted if a mole begins to bleed without reason, becomes persistently itchy, or if the mole rapidly changes color or size over a period of weeks or a few months. Seeking prompt evaluation is the most effective action a parent can take, as early detection significantly improves treatment outcomes for any potential malignancy.
The medical evaluation typically involves a thorough examination of the entire skin surface, often utilizing a specialized magnifying tool called a dermatoscope. For moles that meet multiple warning criteria or are deemed suspicious, the doctor may choose to monitor the spot closely with photographs and measurements, or proceed directly to a skin biopsy. A biopsy involves removing the entire mole or a portion of it to be analyzed under a microscope.
Moles present at birth, known as congenital nevi, also require specialist monitoring. While most small or medium congenital nevi pose little risk, giant congenital nevi, which are larger than 8 inches in diameter, carry an increased risk of developing melanoma, often in the first ten years of life. Children with these larger birthmarks should be under the regular care of a dermatologist to monitor for any nodule formation or other evolutionary changes.