What are moles?

Moles, also called nevi, are present to various degrees on everyone's skin. Moles are round to oval flat spots or raised bumps that are made of collections of melanocytes, the cells that usually exist spread out in the skin to create pigment to protect the skin from sun-generated DNA damage. Moles can be skin-colored, pink, brown, black, or multi-colored. People can be born with moles (congenital nevi), or they can acquire new moles during childhood and early adulthood (acquired nevi). Most people stop getting new moles by their mid-30s. Interestingly, many moles spontaneously disappear with time.

Although most moles are harmless, it is important that they be distinguished from cancers of melanocytes called melanomas. The prognosis of melanoma skin cancer is very much related to how early (or late) it is caught. Regular skin cancer screenings have been shown to decrease melanoma mortality on a population level. In order to assist dermatologists in finding melanomas as soon as possible, is it recommended that all people regularly evaluate their own skin for concerning lesions.

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What signs do I look for in moles?

The ABCDE mnemonic can be used to identify melanomas as soon as possible (ideally look for moles that exhibit 2 of these features):

  • Asymmetry

    Half of a mole does not match the other half in size, shape or color.
  • Border

    The edges of a mole are irregular, scalloped, or poorly defined.
  • Color variability

    A mole has more than one color in it.
  • Diameter

    A mole that is greater than 6 millimeters, or the size of a pencil eraser.
  • Evolving

    Any rapid change in shape, size, texture, or color of a mole is concerning.

An additional useful sign for finding melanomas as soon as possible is the "ugly duckling" sign. Some melanomas can be detected early simply because they look different from surrounding moles, even when they otherwise would not be detected by using the ABCDE mnemonic.

Read more about melanoma and other types of skin cancer here.

Please make an appointment to see our dermatologist right away if you have a mole that you are worried about. A biopsy may be performed to confirm the diagnosis.

Medical Dermatology