Hyperpigmentation is a common, usually harmless condition in which patches of skin become darker in color than the normal surrounding skin. This darkening occurs when an excess of melanin, the brown pigment that produces normal skin color, forms deposits in the skin. Hyperpigmentation can affect the skin color of people of any race.

Age or "liver" spots are a common form of hyperpigmentation. They occur due to sun damage, and are referred to by doctors as solar lentigines. These small, darkened patches are usually found on the hands and face or other areas frequently exposed to the sun.

Melasma or chloasma spots are similar in appearance to age spots but are larger areas of darkened skin that appear most often as a result of hormonal changes. Pregnancy, for example, can trigger overproduction of melanin that causes the "mask of pregnancy" on the face and darkened skin on the abdomen and other areas. Women who take birth control pills may also develop hyperpigmentation because their bodies undergo similar kind of hormonal changes that occur during pregnancy. If one is really bothered by the pigment, the birth control pills should be stopped.

Changes in skin color can result from outside causes. For example, skin diseases such as acne may leave dark spots after the condition clears. Other causes of dark spots are injuries to the skin, including some surgeries. Freckles are small brown spots that can appear anywhere on the body, but are most common on the face and arms. Freckles are an inherited characteristic.

Freckles, age spots, and other darkened skin patches can become darker or more pronounced when skin is exposed to the sun. This happens because melanin absorbs the energy of the sun's harmful ultraviolet rays in order to protect he skin from overexposure. The usual result of this process is skin tanning, which tends to darken areas that are already hyperpigmented. Wearing a sunscreen is a must. The sunscreen must be "broad spectrum" (i.e. it blocks both ultraviolet A and B). A single day of excess sun can undo months of treatment.