What is normal for moles in childhood, how congenital and Spitz nevi behave, how rare pediatric melanoma is, and when to have a spot checked.
Almost every child develops moles, and almost all of those moles are harmless. Melanoma in a child is rare. It does happen, though, and it can look different from the adult version, so parents benefit from knowing both what's normal and what deserves a visit.
Moles, called nevi in medical terms, appear throughout childhood and the teen years. They grow in proportion as the child grows. According to the American Academy of Dermatology, moles in children also commonly darken or lighten, and some fade away.
Sun exposure and family traits both influence the count. A child with fair skin whose parents have many moles will probably have many too. A high count is itself a risk marker later in life, which is one more reason to build sun protection habits early.
About 1 in 100 babies is born with a mole, known as a congenital melanocytic nevus. Doctors classify these by the size they're expected to reach in adulthood. Small means under 1.5 cm, medium is 1.5 to 20 cm, large is over 20 to 40 cm, and giant is over 40 cm. Large and giant nevi are very uncommon. Estimates run from about 1 in 20,000 births for nevi over 20 cm to about 1 in 500,000 for nevi over 40 cm.
Small and medium congenital nevi carry a lifetime melanoma risk of under 1%, according to DermNet. They often become raised, bumpy, or hairy over time, and that change alone isn't a warning sign. Dermatologists generally watch them, with photos if helpful, and remove them only if they change in a worrying way or cause problems.
Giant congenital nevi are different. Lifetime melanoma risk estimates run from 5% to 10%, and most of those melanomas appear before age 10. Some children with large or giant nevi, or with many smaller satellite nevi, also have pigment cells around the brain and spinal cord, so their care usually involves a pediatric dermatologist and sometimes an MRI.
A Spitz nevus is a benign mole seen mostly in children and young adults. About 70% are diagnosed in the first 20 years of life. The classic form is a pink, red, or reddish-brown dome that shows up suddenly and grows quickly over weeks to months, reaching a few millimeters to 1 or 2 cm. Then it typically stops and may stay unchanged for years.
That rapid growth alarms parents, and the alarm is understandable, because a Spitz nevus can resemble melanoma to the eye and under the microscope. Management depends on age and appearance. For a young child with a typical-looking lesion, a dermatologist may monitor it with dermoscopy and photos. For older children and adults, or for lesions that look atypical, removal is more common.
Pathologists recognize a middle category called atypical Spitz tumor, where the features are uncertain. These cases are often sent to a dermatopathologist with special experience in pediatric lesions, and molecular tests may be used to help classify them.
The American Academy of Dermatology puts the number at 300 to 400 cases a year in the United States among children and teens. Most occur in adolescents aged 15 to 19. Melanoma before puberty is rarer still.
Risk factors overlap with those in adults: fair skin that burns easily, many moles, a family history of melanoma, and a history of sunburns. A few uncommon conditions raise risk sharply, including giant congenital nevi, a weakened immune system, and xeroderma pigmentosum, an inherited disorder of DNA repair.
The familiar ABCDE rule (asymmetry, border irregularity, color variation, diameter over 6 mm, evolution) was built from adult melanomas. A study from the University of California, San Francisco (Cordoro and colleagues, Journal of the American Academy of Dermatology, 2013) reviewed 70 patients diagnosed before age 20. Among children aged 10 and under, 60% did not show the conventional criteria. Among those aged 11 to 19, 40% did not.
The authors proposed additional ABCD criteria for children, to be used alongside the standard ones:
In practice, a pediatric melanoma can pass for a wart, a pimple that doesn't heal, or a small blood-vessel growth called a pyogenic granuloma. That resemblance is a main reason diagnosis is sometimes delayed.
Most of these visits end with reassurance. The dermatologist will examine the spot with a dermatoscope and may photograph it for comparison later. If a biopsy is advised, the procedure is done with numbing medicine, and for younger children the office often uses a numbing cream first so the injection is easier to tolerate.
Bring dated phone photos of the spot if you have them. A clear record of how fast something changed is one of the most useful things a parent can give the doctor.
