Suspicious skin moles to worry about

This page was reviewed under our medical and editorial policy by

Frederick L. Durden, Jr, MD, Plastic and Reconstructive Surgeon & Microsurgical Reconstructive Surgeon

This page was updated on October 20, 2022.

It’s important to be aware of changes that appear on the skin over time, as abnormal moles sometimes require medical treatment. Everyone should look over his or her body regularly to look for differences—if any are found, it's important to know what to do next.

While skin cancer is the most diagnosed cancer in the United States, it can almost always be treated if found early. Overall, skin cancer leads to less than 1 percent of all cancer deaths, according to the American Society of Clinical Oncology. Not all abnormal moles are cancerous, so seek advice from a doctor or dermatologist if any signs of skin cancer appear.

Skin cancer is categorized as one of two types: melanoma or nonmelanoma. Squamous cell carcinoma and basal cell carcinoma are both nonmelanoma types, while melanoma skin cancer is less common but faster growing.

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What does an abnormal mole look like?

It’s normal to develop freckles, moles and sunspots throughout life, especially as patients age. However, it’s a good idea to examine moles regularly, looking for anything suspicious that may be cancerous.

Any mole that seems unusual should be examined by a doctor. It also helps to keep in mind the ABCDE rule for skin cancer, which may help patients know what to look for.

  • Asymmetry: This is when a mole is abnormal in size, with the shape of one half not matching with the other half.
  • Border that is irregular: The edges of suspicious moles are ragged, notched or blurred in outline, while healthy moles tend to have more even borders. The pigment of the mole may also spread into the surrounding skin.
  • Color that is uneven: The mole may have various colors present, including black, brown and tan. Areas of white, gray, red, pink or blue may also be present.
  • Diameter: Has the mole increased in size? Melanomas may be tiny, but most are usually larger than the size of a pea (about 1/4 inch).
  • Evolving: This means the mole has changed over the past few weeks or months, either in size, shape or color.

It's also important to look for "ugly duckling" moles, which don't look like the others. Moles that are of a different shape, color, texture or size than other moles may indicate a cancerous growth. In addition, if moles begin to itch, flake, crust or bleed, call a doctor for evaluation.

If a mole fits into one of the above categories, it may be a suspicious mole that needs medical attention. If a mole doesn’t fit into any of the ABCDE categories, but it still stands out, ask the doctor to examine it.

What to do next

After discovering an abnormal mole, it's important to take action as soon as possible. First, make an appointment with a primary care doctor or dermatologist. He or she may examine the mole and ask a series of questions about family and overall health history.

There are different risk factors for melanoma and nonmelanoma skin cancers.

Nonmelanoma risk factors include:

Melanoma risk factors also include a fair complexion and prolonged exposure to UV light, in addition to the following:

  • History of frequent sunburns, especially at a young age
  • Large amount of big or small moles
  • Family history of unusual moles and/or melanoma
  • Being white

Diagnostic tests to tell whether a mole is cancerous

After visiting the doctor, additional diagnostic tests may be needed to learn more about the mole and assess possible treatment options.

The care team may use one or several of the following diagnostic tools.

  • Skin exam: The doctor physically examines the skin, looking for moles that are abnormal in size, texture or color. Point out any concerning moles to the doctor.
  • Skin biopsy: If more information is needed, the doctor may order a mole biopsy. There are four main types of skin biopsies.
    • Shave: A sterile medical razor blade is used to shave off part of an abnormal growth or mole.
    • Punch: An instrument called a trephine (or punch) is used to remove a circle of skin tissue.
    • Incisional: The doctor uses a scalpel to remove part of a mole or growth.
    • Excisional: The doctor removes an entire growth or mole with a scalpel.

If a mole is removed, a local anesthetic or topical cream may be administered to make the procedure more comfortable. It’s typically a quick procedure.

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