If you notice a new mole, you’re in good company. (Hey, Cindy Crawford and Eva Mendes 👋 .) But should you be concerned about new moles appearing on your skin?

Experts think new moles might suddenly appear due to genetic factors, hormonal changes, and sun damage, but they don’t know for sure.

Most moles are also benign (aka noncancerous), but new moles that emerge in adulthood are more likely to become cancerous than ones you’ve had for life.

Still wondering WTF caused this new mole to pop up? Here are the deets on what’s common and when to contact a dermatologist.

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Nemanja Glumac/Stocksy United

Most moles are less than 1/4 inch and range from pink to dark brown or black. They can appear anywhere on your body or face, and usually, show up during childhood and adolescence — though sometimes they can occur later in life.

But not all moles are the same. Plus, moles can change in size and color as you get older. Let’s explain.

Congenital moles

Congenital moles types of birthmarks and vary widely in size, shape, and color. About 0.2 percent to 2.1 percent of infants are born with a congenital mole (the more you know 💫).

Sometimes, these moles are treated later in life for cosmetic reasons (RIP Madonna’s iconic mole). Treatment options include:

  • surgery
  • skin resurfacing (aka dermabrasion)
  • skin shaving (aka excision) of top skin layers
  • chemical peel for lightening
  • laser ablation for lightening

Potential risks: Bigger congenital moles are more likely to become malignant (aka cancerous) in adulthood. Birthmarks bigger than 20 to 40 centimeters have a 4 percent to 6 percent lifetime risk of becoming cancerous. Large clusters of smaller moles around a bigger one also indicate a higher risk.

If your birthmark has grown significantly larger or changed since childhood, it’s worth scheduling an appointment with the derm to ensure it’s safe and healthy.

Acquired moles (aka common moles)

Common moles show up after you’re born, and they can appear anywhere on your skin. According to the American Academy of Dermatology Association, if you have fair skin, you can have anywhere from 10 to 40 of these kinds of moles. If you have darker skin or hair, these moles usually look darker.

Common moles are usually:

  • round or oval shaped
  • flat or slightly raised
  • smooth with distinct edges
  • one solid color (whether brown, black, red, pink, bluish, or skin-colored)
  • unchanging
  • small (1/4 inch or less)
  • hairy (in some cases)

Potential risks: If you have more than 50 common moles, you may have a higher risk of skin cancer. But it’s rare for these moles to become cancerous.

Contact a derm if you have acquired moles or they’ve changed in size or appearance.

Atypical moles (aka dysplastic nevi)

Atypical moles can appear anywhere on your body but rarely appear on your face. They’re more common on the trunk area (your abdomen or back), but they can also show up on your neck, head, or scalp.

These moles are also more common in people who’ve seen a *lot* of sun and have fair skin.

You’ll prob know these weird little guys when you see them because they’re different. Atypical moles can have:

  • irregular shapes with uneven borders
  • various colors (could be a mix of tan, brown, red, or pink)
  • irregular edges or surfaces
  • bigger sizes (more than 1/4 inch)

Benign atypical moles can have some of the same features as melanoma — the most dangerous type of skin cancer — but without the harmful effects. However, atypical moles can also become cancerous.

Potential risks: Though they can become cancerous, only about 1 in 10,000 atypical moles turn into melanoma each year. Since they can look alike, though, it’s good to have regular skin checks with a derm to monitor any changes in these moles.

Are you at risk of melanoma?

It’s common to experience a greater risk of melanoma if you have:

  • more than five atypical moles
  • a blood relative who had melanoma
  • previously had melanoma

If people in your fam have lots of atypical moles, you might have familial atypical multiple mole melanoma (FAMMM) syndrome. Your 10-year risk of melanoma is 10.7 percent if you have the syndrome (17.3 times higher than people without it). Plus, the lifetime risk of folks with FAMMM syndrome inches to 100 percent.

Don’t fret, though: Get checked. Melanoma is highly curable when caught early.

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Even though we don’t totally understand why moles pop up in adulthood, here are some potential causes of benign and cancerous moles.


If you and your relatives are similarly spattered in moles, surprise! it probably runs in the fam. People with fair skin, light, or red hair are also more likely to have existing moles or develop them later in life.

Another reason you and your family are prone to moles might be genetic mutations. A 2015 research review found that BRAF gene mutations exist in 78 percent of benign acquired moles — those noncancerous moles that pop up later in life.

The BRAF mutation is also involved in acquired moles that turn into melanoma. But researchers don’t know the exact reason a benign mole turns into a cancerous one.

Sun exposure

Bronzed-to-a-crisp skin was all the rage in the 2000s (sorry, derms!). But that past sun exposure, tanning beds, and sunburns can lead to *a lot* of acquired moles.

Sun exposure can also lead to skin damage and moles that lead to melanoma or other skin cancers. Remember: Sunscreen is your friend!

Suppressed immune system

Moles can sometimes pop up due to your body’s response to certain medications. Many medications have been found to cause moles, especially those that suppress the immune system. People who take immunosuppressant drugs after an organ transplant actually tend to have a higher risk of skin cancer.

So, while the pros don’t understand exactly what’s at work, the immune system def seems to play a role in potentially-cancerous or atypical mole formation.

Hormonal changes

Scientists also think that moles are related to hormones, potentially during hormonal shifts like puberty, pregnancy, or menopause.

In a 2014 study, researchers also found that some moles may be linked to hormone blood levels tied to breast cancer risk. Just note, research was limited to a group of white female nurses, so we don’t know the full scope for all women. Plus, researchers don’t know exactly what’s at work here.

Anytime a mole you’ve had forever changes shape or color, or a new fella pops up, it’s wise to contact a derm to get things checked out.

And if your mole itches, bleeds, oozes, or hurts, definitely make an appointment with a derm.

New moles are more likely to become cancerous than ones you’ve had for life. But a 2017 research review also found 71 percent of melanomas did not pop up from a mole.

Melanoma is the most life threatening (and rarest) skin cancer, but new moles could also be a symptom of basal cell or squamous cell cancers too. These types usually appear in areas exposed to the sun, like the face, head, or neck. Thankfully, they’re relatively easy to treat if you catch them early.

Wondering if your new mole is a prob?

Here’s the American Academy of Dermatology’s ABCDEs of melanoma warning signs:

  • Asymmetrical. For example, each side of it looks different.
  • Border. The mole has irregular borders.
  • Color. The mole’s changed color or has several or mixed colors.
  • Diameter. It’s grown over time or is bigger than 1/4 inch in diameter.
  • Evolving. It keeps changing in size, color, shape, or thickness.
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Doing a skin self-check can help you keep tabs on new moles and mole changes. Here’s how to check your skin for symptoms of skin cancer:

  1. Look at your entire body in a full-length mirror. Start looking at the front, then the back, and then your right and left sides with your arms raised up so you can see your armpits.
  2. Check out your underarms, forearms, between your fingers, and your palms. Lift one elbow to start, and focus on one arm at a time.
  3. Check your legs, between your toes, and soles of your feet. Sitting on a chair can help you bring in your feet for a closer look.
  4. Look at your neck and scalp. Use a hand mirror and part your hair for hard-to-see areas.
  5. Check your back and butt. Use that hand mirror again to get a closer look.

Melanomas can develop anywhere on the skin, but they’re more likely to start on the trunk (chest and back) in men and on the legs in women.

People of Color often have a lower risk of melanoma, but melanoma typically shows up in hard-to-see places like the soles of the feet, palms, between fingers and toes, and underneath the fingernails and toenails.

Just keep in mind, it’s easy to miss subtle changes in moles, so you should still have a derm to check out any new or changing moles.

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Again, moles that suddenly show up in adulthood or change in color or shape should be checked out by a dermatologist. Experts also recommend people with moles see a derm for yearly skin checks.

If you have an especially high melanoma risk, your doc may recommend checkups as often as every 6 months.

🚨 If you have a mole that keeps changing or that fits any criteria in the ABCDE guide (Asymmetrical, with an irregular Border, changing Color, bigger Diameter than 1/4 inch, or Evolving in appearance), contact a doc ASAP! 🚨

But don’t let your skin get you stressed. When detected early, melanoma is super treatable. When spotted early, the 10-year survival rate is 93 percent.

Though experts don’t know for sure, moles might appear due to a combo of factors like genes, sun exposure, and hormonal shifts.

Since some acquired moles — especially ones you get later — can become cancerous, connect with a derm for a complete assessment if you notice a new one pop up. It’s also a good idea to contact a doc if your moles change drastically in appearance over time.