Most people have at least some moles, with the average person with light skin having between 10 to 40, according to the American Academy of Dermatology (AAD). Moles can be raised or level with the skin, and while they're usually a shade of brown, they can be black, pink or even blue. Some moles have hair and others don't. Though most moles are benign, changes in their appearance or new growths require a visit to your dermatologist, as this can indicate melanoma.
Congenital Moles
Moles present from birth are called congenital moles or congenital nevi. One in 100 people have congenital moles, according to the AAD. These skin moles have a wide size range; they are considered small when under 1.5 cm, and giant when more than 20 cm. Congenital moles are typically rounded, evenly toned (though sometimes speckled), have clear boundaries and are sometimes raised. They may be smooth or have a bumpy texture, and may have thick, dark hair growing from them. Melanoma can develop in congenital moles, and the chances are significantly greater in giant ones, explains the AAD.
Acquired Moles
Moles that appear some time after birth are known as acquired moles or acquired nevi. The AAD says the risk of melanoma is highest in those who develop more than 50 such skin moles. Most common in people with fair complexion, the earliest acquired moles tend to appear between 6 months and 1 year of age, and continue through childhood and adolescence, according to the Dermatology Channel of Health Communities. These types of moles can have widely varying appearances, though their average diameter is 3 to 5 mm, and they generally have well-defined borders. Acquired moles can be surgically removed for either medical or cosmetic reasons, and sun protection through childhood is the best preventative measure.
Atypical Moles
Atypical moles, otherwise known as dysplastic nevi, carry the greatest risk of developing melanoma, according to the AAD. The American Osteopathic College of Dermatology cites that one in 10 Americans has at least one atypical mole, and heredity plays a part in their development. Their appearance can vary, but they are best identified by irregularities as compared to other types of moles. Often, their coloration is uneven or not a shade of brown, their borders aren't well-defined, their shapes are not round and they may be larger than the average acquired moles. Your dermatologist should evaluate atypical moles, and they should be closely monitored for any changes. A biopsy may be performed to determine whether these skin moles are cancerous.
