Table of ContentsView AllTable of ContentsCauses of MolesTypesMole Changes and Warning SignsSkin Self-ChecksWhen to Contact a Healthcare Provider
Table of ContentsView All
View All
Table of Contents
Causes of Moles
Types
Mole Changes and Warning Signs
Skin Self-Checks
When to Contact a Healthcare Provider
Moles, also known asnevi, are very common. Most people have about 10 to 40 moles that form between childhood and adulthood.
A mole occurs as a concentration of skin cells calledmelanocytes(cells that produce pigment). They may form in response to ultraviolet (UV) light exposure or changing hormone levels.
Though most moles are harmless, you should not ignore them. New moles or moles that change can be signs ofmelanoma(skin cancer). Early detection is key to successfully treating this fast-spreading type of skin cancer.
This article explains how new moles form, the types of moles, and what mole traits may be signs of skin cancer.
Anastasiia Yanishevska / Getty Images
What Causes a New Mole to Appear?
Moles appear when melanocytes in yourepidermis(the top layer of skin) become overgrown and develop in groups. While melanocytes are normally present in your body, internal and external factors can trigger changes that result in moles.
Moles begin appearing in childhood and continue throughout your lifetime.
UV Radiation
UV radiation from the sun or tanning beds is a common cause of moles that appear from childhood into adulthood. When exposed to UV light, melanocytes producemelanin(a protective, skin-darkening pigment) and cluster to form moles.
The impact of UV radiation on melanocytes is why most moles occur on parts of your body that receive the most sun exposure. You may notice the eruption of new moles after spending an extended period in the sun.
Hormonal changes
Moles are more likely to occur during periods when your hormones are very active, such as adolescence and pregnancy. These changes are related to the estrogen receptors in pigment cells. When extra estrogen is circulating, it can trigger these receptors and result in hormone-related skin changes like moles.
Certain characteristics
Having the following characteristics increases your risk of new moles appearing throughout your lifetime:
Freckles vs. Moles: Understanding the Difference
Types of Moles
Not all moles are alike. The most common types of moles include the following:
Acquired Moles (Common Moles)
Reproduced with permission from © DermNet dermnetnz.org 2023
Moles appearing on your skin after birth are called acquired moles. They are also called common moles and are typically harmless. Most adults have between 10 and 40 acquired moles.
Acquired moles usually appear in childhood and early adulthood through age 40, though they can develop anytime. Common characteristics of acquired moles include the following:
Congenital Moles
Atypical Moles (Dysplastic Nevi)
Atypical moles, also calleddysplastic nevior Clark’s nevi, are present in about 10% of people in the United States. These moles typically have the following characteristics:
Spitz Nevus
Reproduced with permission from © DermNet dermnetnz.org 2023
ASpitz nevusis a rare, benign mole that is usually acquired. It often has some of the same features as melanoma. A Spitz nevus so closely resembles a melanoma that it can’t be identified visually. A Spitz nevus often has the following characteristics:
Is an Itchy Mole a Sign of Melanoma?
While most moles, brown spots, and other skin growths do not pose a health threat, some represent the first warning signs of melanoma.
Benign moles do not typically change in shape, size, or texture. Certain changes to existing moles, the appearance of a new mole, or the eruption of a spot that looks different from the other spots (known as the “ugly duckling” sign) can be early warning signs of skin cancer.
Melanomas
This photo contains content that some people may find graphic or disturbing.See PhotoReproduced with permission from © DermNet and © Waikato District Health Boardwww.dermnetnz.org2023.
This photo contains content that some people may find graphic or disturbing.See Photo
This photo contains content that some people may find graphic or disturbing.
Reproduced with permission from © DermNet and © Waikato District Health Boardwww.dermnetnz.org2023.
Use the ABCDE rule to identify possible signs of melanoma. Contact your healthcare provider about any mole that has one or more of the following characteristics:
What Are the ABCDEs of Melanoma?
Performing regular skin self-checks can help you identify mole changes and signs of melanoma early. Doing this can improve your chances of getting early and successful treatment. Most skin cancers are highly curable when diagnosed and treated early.
While there is no consensus regarding how often you should perform a skin self-check, the Skin Cancer Foundation advises performing them at home monthly. Your healthcare provider can advise on how often you need skin self-checks based on your risk factors for skin cancer.
Before doing your first skin self-check, look at photos of melanoma in different stages to know the features of a suspicious mole. Record the patterns of freckles, moles, and blemishes to compare changes in later months.
To perform a skin self-check, use a well-lit room. Stand in front of a full-length mirror without clothing. Use this process to perform a comprehensive exam:
In addition to performing monthly skin self-checks, the Skin Cancer Foundation advises that you see adermatologistannually for a total body skin examination. If you have a high risk of skin cancer, you may be advised to have these types of professional exams more frequently.
How to Prevent Skin Cancer
About 50% of melanomas are self-detected. When melanoma is detected and treated before it spreads to the lymph nodes, there is a 99% survival rate.
A mole that fits the ABCDE criteria should be reported to your healthcare provider. A healthcare provider should also examine moles with any of the following characteristics:
How to Tell the Difference Between Skin Cancer and a Mole
Summary
Moles are common skin growths that consist of clusters of melanocytes. They often grow in response to hormonal changes or UV light exposure. While most moles are benign and harmless, some moles occur as the first sign of skin cancer.
A healthcare provider should examine moles that change in size, shape, or texture. New bleeding or itching at the site of a mole should also be checked.
Monthly skin self-checks can help you find the changes that may lead to problems. Finding mole changes and getting prompt treatment can increase your chances of curing skin cancer when it exists.
16 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
American Osteopathic College of Dermatology.Moles.
Houston Methodist.When should I worry about a mole?
Mercy Health.What are moles?
The University of Texas MD Anderson Cancer Center.Pregnancy-related skin changes or skin cancer?
National Cancer Institute.Common moles, dysplastic nevi, and risk of melanoma.
Cincinnati Children’s.Moles (congenital melanocytic nevi).
City of Hope.Types of moles.
American Osteopathic College of Dermatology.Spitz nevus.
American Cancer Society.Signs and symptoms of melanoma skin cancer.
Skin Cancer Foundation.Melanoma warning signs.
American Academy of Dermatology Association.Skin cancer.
Skin Cancer Foundation.How to do a skin check.
AIM at Melanoma Foundation.How to do a skin self-examination.
The Skin Cancer Foundation.Annual exams.
American Cancer Society.How to spot skin cancer.
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