Moles (Nevi)

Melanocytes produce melanin, the pigment that gives skin its natural color. When skin is exposed to the sun, melanocytes produce more pigment, causing the skin to tan, or darken. Sometimes, clusters of melanocytes and surrounding tissue form noncancerous growths called moles. (A mole is also called a nevus, or the plural, nevi.)

Moles are very common. Most people have between 10 and 40 moles. Moles may be pink, tan, brown, or a color that is very close to the person’s normal skin tone.

Nevi (moles), normal

People who have dark skin tend to have dark moles. Moles can be flat or raised and may darken during pregnancy or after sun exposure. Flat moles are called junctional nevi and raised moles are called compound nevi. They are usually round or oval and smaller than a pencil eraser. They may be present at birth or may appear later on—usually before age 40. They tend to fade away in older people. When moles are surgically removed, they normally do not return.

A halo nevus occurs when the skin surrounding a mole loses its pigmentation or color. This is benign and often the central mole and white ring will disappear with time. Halo nevi are most common in children and teenagers.

Most moles are harmless and do not require treatment. If you have moles, keep an inventory of their number and appearance. Change in size, shape or color of a mole is cause for medical evaluation. Moles that develop in adult life should also be evaluated.

Sun protection with appropriate clothing and sunscreen are the best way to avoid mole development.