A mole is a small growth on the skin that forms when pigment-producing cells, called melanocytes, cluster together instead of spreading evenly. Most people have between 10 and 45 moles, nearly all of which are harmless. They typically appear during childhood and the teenage years, and new ones can continue to develop into your 40s.
What Moles Look Like
A typical mole is round or oval, smaller than about 5 millimeters wide (roughly the width of a pencil eraser), and has a smooth surface with a clearly defined edge. The color is usually uniform: pink, tan, or brown. Many are slightly dome-shaped, though some sit flat against the skin. They can show up anywhere on the body, including the scalp, between fingers, and under nails.
Moles that are present at birth are called congenital moles. Those that develop later in childhood or adulthood are called acquired moles, and they make up the majority of the moles on most people’s skin.
How Moles Change Over a Lifetime
Moles aren’t static. They tend to darken slightly during puberty and pregnancy, largely due to hormonal shifts. During adulthood, many moles gradually lose their pigmentation, and some may fade so much they seem to disappear in old age. These normal changes happen very slowly, over years or decades, which is an important distinction from the rapid changes (over weeks to months) that can signal a problem.
Why Some People Have More Moles
Two main factors influence how many moles you develop: genetics and sun exposure. If your parents have many moles, you’re more likely to as well. A rare inherited condition called FAMMM syndrome, caused by a mutation in a specific gene involved in cell growth regulation, produces an unusually large number of moles and significantly raises the risk of melanoma and pancreatic cancer.
Ultraviolet radiation from the sun also plays a direct role. Sun exposure can trigger the formation of new moles, and trials have shown that protecting children’s skin from the sun reduces the number of new moles that develop. UV light damages DNA in skin cells, which can cause melanocytes to multiply in ways they normally wouldn’t.
Common Moles vs. Atypical Moles
Not all moles look the same, and the differences matter. A common mole is small, evenly colored, and symmetrical. An atypical mole (also called a dysplastic nevus) looks noticeably different. It’s usually wider than 5 millimeters, has a mixture of colors ranging from pink to dark brown, and its edges are irregular, sometimes fading into the surrounding skin rather than stopping at a clear border. The surface can be smooth, slightly scaly, or pebbly, and it tends to be flat rather than dome-shaped.
Having atypical moles doesn’t mean you have cancer. But having many of them does increase your overall risk, especially if you also have a family history of melanoma. The more atypical moles you have, the more carefully you should track changes in your skin over time.
When a Mole Might Be Something More
The chance of any single mole turning into melanoma is extremely low. For men and women under 40, the annual transformation rate is 1 in 200,000 or less per mole. Even for men over 60, the highest-risk group, it’s roughly 1 in 33,000 per mole per year. Still, melanoma is serious enough that knowing the warning signs matters.
The ABCDE rule is the standard framework for spotting suspicious changes:
- Asymmetry: one half of the mole doesn’t match the other.
- Border: the edges are ragged, notched, or blurred, and pigment may spread into surrounding skin.
- Color: the mole contains uneven shades of black, brown, tan, white, gray, red, pink, or blue.
- Diameter: the mole is larger than 6 millimeters (about the size of a pencil eraser), though melanomas can sometimes be smaller.
- Evolving: the mole has changed in size, shape, or color over the past few weeks or months.
The last one is arguably the most important. A mole that has looked odd for years but hasn’t changed is less concerning than a previously normal mole that’s shifting rapidly. Speed of change is the key signal.
Skin Screening: What the Guidelines Say
You might assume that regular full-body skin checks by a doctor are standard advice, but the U.S. Preventive Services Task Force has found insufficient evidence to recommend routine visual skin screening for people without symptoms or a personal or family history of skin cancer. No major U.S. professional organization currently recommends it for the general population. That said, if you notice any ABCDE changes, have a family history of melanoma, or have many atypical moles, screening conversations with a dermatologist are appropriate. The guidelines are about population-wide screening, not about ignoring something that looks wrong.
How Mole Removal Works
Moles are removed for two reasons: to test suspicious tissue or simply because the mole is bothersome (catching on clothing, for example). Both procedures are quick, outpatient, and done under local numbing.
A shave removal uses a razor-like blade to shave the mole down to the level of the surrounding skin. It’s simpler and works well for raised moles that aren’t suspicious for deep skin cancer. The trade-off is that moles removed this way are somewhat more likely to grow back, and the technique can’t evaluate deeper layers of tissue.
A surgical excision cuts the mole out entirely, along with a small margin of healthy skin around it, then closes the area with stitches. This method is preferred when a mole needs to be fully examined under a microscope, particularly if there’s any concern about atypical cells.
Either way, healing takes about two to three weeks. Most people drive themselves home from the appointment and return to normal activities the same day. Scarring is common but typically fades over time, and the degree depends on the size and location of the mole.