Everyone has moles (also known as "nevi"),
sometimes 40 or more. Most people think of a mole as
a dark brown spot, but moles have a wide range of appearance.
They can be raised from the skin and very noticeable,
they may contain dark hairs, or they may be dangerous.
Moles can appear anywhere on the skin, alone or in
groups. They are usually brown in color and can be
various sizes and shapes. The brown color is caused
by melanocytes, special cells that produce the pigment
melanin. Moles probably are determined before a person
is born. Most appear during the first 20 years of a
person's life, although some may not appear until later
in life. Sun exposure increases the number of moles.
Each mole has its own growth pattern. At first, moles
are flat and tan, pink, brown or black in color, like
a freckle. Over time, they usually enlarge and some
develop hairs. As the years pass, moles usually change
slowly, becoming more raised and lighter in color.
Some will not change at all. Most moles will slowly
disappear, seeming to fade away. Others will become
raised so far from the skin that they may develop a
small "stalk" and eventually fall off or
are rubbed off. This is the typical life cycle of the
common mole. These changes occur slowly since the life
cycle of the average mole is about 50 years. Moles
may darken, with exposure to the sun. During the teen
years, with birth control pills and pregnancy, moles
often get darker and larger and new ones may appear.
More information on this and other dermatologic conditions at our
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