Skin discolorations are common on the skin. For many, they can be birthmarks resulting from simple and harmless factors, such as a highly concentrated spot of melanin in your skin. Other times, though, discolorations can be a cause for concern and may indicate more serious trouble on the horizon. And while most skin discolorations are dark, some can result in a lighter skin color. A discoloration of your skin might occur for a number of reasons.
Exposure to sunlight can cause skin darkening in two different ways. More common developments are age spots that develop over time and are irregular in shape. Age spots are more common as people grow older and occur when the sun damages the production cycle of pigment in your skin. The other way sunlight creates discoloration is called melasma and is characterized by brown stains developing on the face or chest. It is found in pregnant women or those taking birth control that disrupts the regulation of hormones in your body, causing melanin to accumulate unevenly in your skin. With exposure to sunlight, certain parts of your skin will darken faster than others and can make a noticeable difference, although these discolorations will disappear over time.
Melanin can crop up in concentrated bunches under your skin, causing visible--and permanent--discolorations. These can be present from birth but can also develop later in life. This type of discoloration is what common birthmarks are the result of, and skin moles also develop in this manner. Moles can be flat or raised on the skin, may have irregular shapes--like age spots--and can also disappear over time, although they can also be removed with lasers or freezing methods.
The loss of pigment is called vitiligo, and it can affect 1 percent of all individuals. Though the exact cause is unknown, Discovery.com reports that it may result from abnormal nerve cells that halt the production of pigment in your skin, or it could result from an autoimmune problem in which the body's white blood cells attack and kill pigment cells. Individuals with thyroid disorders, anemia, excessive adrenal gland function or alopecia are more likely to develop this type of discoloration.