Skin Moles: When Is a Mole a Concern?

What moles are

Moles form when melanocytes, the cells that make skin pigment, grow in a cluster instead of being spread evenly. They can be flat or raised, smooth or slightly rough, and may have hair. Most appear before age 30. Sun exposure in childhood and genetics determine how many you get.

Common types of moles

Spots that look like moles

• Seborrheic keratoses: waxy, "stuck-on" brown spots in older adults. Harmless.
• Freckles and sun spots (solar lentigines): flat, light brown, on sun-exposed skin.
• Dermatofibromas: firm, brownish bumps, often on the legs, that dimple when pinched.
• Cherry angiomas: small bright red dots.
• Basal cell carcinoma: a pearly bump or non-healing sore, sometimes pigmented.

Warning signs: the ABCDEs of melanoma

• A, Asymmetry: one half does not match the other.
• B, Border: edges are ragged, notched or blurred.
• C, Color: several shades of brown, black, red, white or blue in one mole.
• D, Diameter: larger than 6 mm (about a pencil eraser), though melanomas can be smaller.
• E, Evolving: any change in size, shape, color, height, or new symptoms such as itching, bleeding or crusting.

Evolving is the most important sign. Most melanomas arise as new spots, not from existing moles.

The ugly duckling sign

Most of a person's moles look alike. A mole that stands out, darker, larger, a different shape, or the only pink one among brown moles, is the "ugly duckling" and should be checked.

Nodular melanoma

Some melanomas do not follow the ABCDE rule. Nodular melanoma grows as a firm, raised, dome-shaped bump that may be black, red or skin-colored, and grows over weeks. Remember EFG: Elevated, Firm, Growing.

Who is at higher risk of melanoma

• more than 50 moles, or several atypical moles
• fair skin, red or blond hair, light eyes, freckling
• a history of blistering sunburns, especially in childhood
• indoor tanning
• a family history of melanoma
• a weakened immune system
• previous melanoma or other skin cancer

How to check your moles

1. Once a month, check your skin in good light with a full-length and a hand mirror.
2. Look everywhere, including the scalp, between toes, soles, palms, under nails and the genital area.
3. Take photos of moles you are watching, with a ruler for scale, to compare over time.
4. Ask a partner to check your back and scalp.

What a dermatologist does

A dermatologist examines your skin, often using a dermatoscope, a handheld magnifier with light that shows patterns under the surface. Moles may be photographed and rechecked in 3 months to look for change. Suspicious moles are removed by excision or a deep shave biopsy under local anesthetic and sent to a lab.

If melanoma is found early, while it is thin, simple surgery cures most cases. That is why early checking matters.

Removing harmless moles

Benign moles can be removed for cosmetic reasons or if they catch on clothing. Removal leaves a small scar. Do not remove moles yourself with creams, cutting or freezing kits, which can cause scarring and infection and destroy tissue needed to diagnose melanoma.

Preventing new moles and melanoma

• Seek shade between 10 a.m. and 4 p.m.
• Use broad-spectrum sunscreen SPF 30 or higher, reapplied every 2 hours and after swimming.
• Wear protective clothing, a wide-brimmed hat and sunglasses.
• Avoid tanning beds.
• Protect children from sunburn, as childhood exposure strongly affects mole numbers.

Frequently asked questions

When should I worry about a mole?

See a doctor if a mole is changing in size, shape or color, has an irregular border or several colors, is larger than a pencil eraser, looks different from your other moles, or itches, bleeds or crusts. A new mole after age 30 to 40 should also be checked.

Is it normal to get new moles as an adult?

New moles are common until about age 30 to 40. After that, new pigmented spots are more likely to be other things, such as seborrheic keratoses or sun spots, and occasionally melanoma. Any new, changing or unusual spot in adulthood should be checked by a doctor.

Can a mole turn into cancer?

It can, but rarely. The lifetime chance of any single common mole becoming melanoma is very low, and most melanomas appear as new spots. People with many or atypical moles have a higher overall risk, so regular skin checks are recommended for them.

Should a mole that itches be checked?

Occasional itching from dry skin or clothing rubbing is common. A mole that itches persistently, especially if it is also changing, bleeding or crusting, should be examined by a doctor or dermatologist.