Moles (nevi) are a common type of skin growth. They often appear as small, dark brown spots and are caused by clusters of pigment-forming cells (melanocytes). Most people have 10 to 40 moles that appear during childhood and adolescence and may change in appearance or fade over time.
It's thought to be an interaction of genetic factors and sun damage in most cases. Moles usually emerge in childhood and adolescence, and change in size and color as you grow. New moles commonly appear at times when your hormone levels change, such as during pregnancy. Most moles are less than 1/4 inch in diameter.
Color that is uneven: Shades of black, brown, and tan may be present. Areas of white, gray, red, pink, or blue may also be seen. Diameter: There is a change in size, usually an increase. Melanomas can be tiny, but most are larger than the size of a pea (larger than 6 millimeters or about 1/4 inch).
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