Moles (Nevi)


What Is It?

Common moles are small, pigmented spots on the skin that usually appear during childhood or adolescence, although they are sometimes present at birth. They are composed of clusters of pigmented cells called melanocytes. Moles may multiply in number during adolescence and pregnancy, and existing ones may enlarge or darken somewhat during these times. Despite such changes, moles should always remain:

  • Evenly pigmented
  • Sharply demarcated
  • Symmetrical in shape and color


Moles can vary in color. They can be flesh-colored, yellow-brown or black. They also can be flat or raised and can be smooth, hairy or warty. Although moles usually do not become cancerous, a malignant melanoma can begin as a mole. For this reason, it is important to monitor moles and have them examined by a dermatologist if they:

  • Enlarge suddenly
  • Develop an irregular border
  • Darken or become inflamed
  • Show spotty color changes
  • Begin to bleed, crack or itch
  • Become painful

Moles called atypical moles, or dysplastic nevi, have somewhat different physical characteristics and sometimes run in families. They are more likely than common moles to turn into cancer. Simple dysplastic nevi are common, but people with multiple dysplastic nevi and melanoma in two or more first-degree relatives have 25 times the risk of developing melanoma. This is called the dysplastic nevus-melanoma syndrome.


Your doctor can determine the type of mole you have by looking at it:

Common moles are generally no more than 1 to 10 millimeters (usually less than half an inch) in diameter. They are flesh-colored, yellow-brown or black and can be located anywhere on the body. They appear during childhood or adolescence.

Atypical moles (dysplastic nevi) are usually larger in diameter (5 to 12 millimeters). They are tan to dark brown with a pink background and may have a mixture of colors, including tan, brown, pink and black. The border is irregular and indistinct and often fades into the surrounding skin. Most commonly, atypical moles appear on sun-exposed skin, but they can occur elsewhere, and they continue to develop after age 35.

Expected Duration

Most moles never become a problem. However, moles should be inspected regularly for any abnormal changes.


When melanocytes become cancerous, they are called melanomas. It is important to examine your moles regularly to look for any suspicious changes. Get someone else to inspect your scalp and other areas that are hard to see. Watch for the early warning signs of melanoma by using the ABCDE criteria:

  • Asymmetry
  • Border irregularities
  • Color variation (different colors within the same mole)
  • Diameter greater than 6 millimeters (larger than a pencil eraser)
  • Enlargement

Practice safe sunning. Never sunbathe or visit a suntan parlor for the sake of tanning. Use high-SPF sunscreen when outdoors, wear protective hats and clothing, and avoid the outdoors when the sun is most intense, from 11 a.m. to 3 p.m.


Common moles do not need to be removed. However, some people choose to have them removed for cosmetic reasons; if they are raised and located in areas where clothing irritates them, such as the waistline; or if they are on the scalp and are irritated by hair brushing. Most moles can be cut off in a simple in-office procedure. Moles and dysplastic nevi whose appearance suggests they may be cancerous should be removed and examined under a microscope. If they are found to be cancerous, additional skin in the surrounding area also must be removed.

When To Call A Professional

Do not ignore warning signs. Have suspicious moles checked by a dermatologist. Melanoma is the deadliest form of skin cancer, but early diagnosis could save your life. Your doctor will perform a biopsy if a mole appears abnormal. Also, having a doctor check your moles once is not sufficient. Normal-looking moles can become cancerous later. Moles must be reexamined from time to time, especially if you notice any changes. If you have dysplastic nevi or if there is a history of melanoma in your family, you should have a physician check all of your moles regularly. Your physician will recommend the frequency needed for follow-up care.


Although moles can become cancerous, most remain benign throughout a person’s lifetime and pose no health problem.

Johns Hopkins patient information

Last revised:

Diseases and Conditions Center

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.