MOLES

A mole is a growth on the skin that can be flesh-colored, brown, or black. Moles can appear anywhere on the skin, either singly or in groups. Most moles emerge during the first twenty years of life, although some may not appear until later. It is common to have between 10 and 40 moles by adulthood. As one ages, moles can change, becoming raised, changing color, or even fading away. Often, hairs may grow from a mole.

WHAT CAUSES A MOLE?

Moles develop when skin cells called melanocytes grow in clusters rather than being spread out across the skin. These cells produce melanin, which colors the skin. Moles may darken after exposure to sunlight, during adolescence, and during pregnancy. The primary cause of moles is genetic, though excessive exposure to ultraviolet rays can also lead to the formation of moles.

WHAT ARE CONGENITAL NEVI?

Congenital Nevi are moles present at birth, occurring in about one in 100 people. These moles are more likely than others to develop into melanoma, especially if they are larger than eight inches in diameter.

WHAT ARE DYSPLASTIC OR ATYPICAL NEVI?

Dysplastic or Atypical Nevi are benign moles that may look similar to melanoma but are not cancerous. However, having these types of moles can increase the risk of developing melanoma, especially if there are many of them. These moles often run in families.

HOW DO I KNOW IF A MOLE IS CANCEROUS?

While most moles are harmless, those that look different from others or appear after age 20 should be checked by a dermatologist. Changes in a mole’s color, size, shape, or height are concerning, as are symptoms like bleeding, oozing, itching, scaling, or pain.

Examine your skin regularly, especially parts exposed to the sun like hands, arms, chest, neck, face, and ears. Use a mirror or ask for help to check areas you can't see easily. The following ABCDEs are important signs of potentially cancerous moles:

  • A – Asymmetry: One half of the mole does not match the other.

  • B – Border Irregularity: The edges of the mole are ragged, blurred, or irregular.

  • C – Color: The mole has uneven coloring with shades of tan, brown, black, blue, white, or red.

  • D – Diameter: The mole is larger than the eraser of a pencil.

  • E – Elevation or Evolution: Part of the mole is raised above the skin or has changed over time.

See our Skin Cancer page for more information.

HOW ARE MOLES TREATED?

If a mole appears suspicious, your dermatologist may perform a biopsy by removing a small section of the mole to examine it more closely under a microscope. If the mole is cancerous, and only a section was initially removed, the dermatologist will remove the entire mole, including a margin of normal skin.

Protecting yourself from sun exposure, monitoring your skin for changes, and regular dermatological check-ups can reduce your risk of skin cancer.