When you have darker patches of skin, you have hyperpigmentation which is the result of an over production of melanin within the skin cells in that area. Melanin is the chemical within your body that creates browning of the skin. Suntans, your bodys way of protection when exposed to the suns rays, are a result of increased melanin production. The spots that form on older skin, often called age or liver spots, are really hyperpigmentation from sun damage and usually on the hands and face. While hyperpigmentation is much more obvious on Caucasians, it happens to all races.
Scarring due to abrasion, burns, acne, and other things can result in hyperpigmentation as well. Surgeries may also cause it. Keep in mind that not every injury to the skin or surgery is going to cause hyperpigmentation.
Genetics can also be a factor in hyperpigmentation. The obvious signs of this are freckles. These are affected by both genetics and other sources (such as sunshine or hormones). When genetics mix with another factor which is a known trigger for hyperpigmentation, there is usually an increase in the size of the freckles and they will become darker. When the extra source is removed, the freckles tend to subside back to the normal number and color.
Another form of hyperpigmentation that you may have heard of is the mask of pregnancy which is triggered by the hormonal changes that women experience with pregnancy. This is most often found on the face but may appear on the abdomen as well. Birth control pills and other hormonal birth control methods make the body mimic pregnancy and can also cause this form of hyperpigmentation. Usually this hyperpigmentation goes away after the hormones are able to resume their normal levels, which is after pregnancy or after stopping birth control pills (or other hormonal birth control).
You have probably heard of products designed to get rid of freckles and other forms of hyperpigmentation. Many of them actually do work because of a bleaching agent called hydroquinone. Those that contain hydroquinone do actually lighten the hyperpigmentation. You can find many of these in stores and at cosmetics counters in a half strength formula but to get stronger products, you will need a prescription.
More severe cases may be prescribed a cream which is a combination of tretinoin and cortisone. The newest treatment for hyperpigmentation is the laser treatment. This does not work for everyone, so your dermatologist or plastic surgeon will need to do a test spot on a hidden area of your skin first. This test spot is important because on some people, laser treatments work in reverse. In other words, instead of getting rid of the hyperpigmentation, they make it worse.
If you are troubled by hyperpigmentation, you may want to look at the possible causes and see if they are part of your life. If so, you should try to avoid the triggering factor before you try other methods of removal. No matter the form of removal, the skin will not get better overnight; it will have to grow off after the medication balances the melanin production. This means that your skin will have to balance, renew itself and shed the over pigmented cells before you can see a difference, so you should allow about 6 months of time without the trigger before you decide to seek alternate methods of removal. To avoid sunshine, you will need to get a good, full spectrum sunscreen; hormones from birth control can only be avoided by stopping hormonal birth control therapies.