Hyperpigmentation is a common condition in which some patches of skin turn darker in color. This is a harmless condition caused when there is too much brown pigment, called melanin, in the skin. This condition can affect people in all races.
Age spots, sometimes called liver spots, are a form of hyperpigmentation. They usually occur because of damage to the skin from the sun. Doctors call these spots solar lentigines. The small, dark spots are found generally on the hands and face, but any area exposed to a lot of sun can be affected.
There are two types of spots that are similar to age spots, but they cover larger areas of skin. These are referred to as melasma or chloasma spots and, while they are similar to age spots, they are a result of hormonal changes. Some pregnant women overproduce melanin and they get a condition called "mask of pregnancy" on their faces or abdomens. Women who take birth control pills may also develop hyperpigmentation since their bodies react, hormonally, as if they were pregnant.
Hyperpigmentation is not the only cause of skin color change. Acne can cause darkening of the skin and so can skin injuries and some surgery. Freckles are darkened places on the skin of the face and arms and is a hereditary condition.
Any darkened skin patch can get even darker when that area of the skin is exposed to the sun because melanin absorbs ultraviolet rays from the sun in order to protect the skin from overexposure. This is actually what we refer to as "tanning."
There are a variety of prescription creams that can help to lighten the darkened patches of skin. They do this by slowing melanin production so that the patches fade. Laser treatments are also effective at removing hyperpigmentation and often can remove the pigmented areas without leaving any scars.