Melanin and Pigmentation

Uneven pigmentation affects most people, regardless of ethnic background or skin color. Skin may either appear lighter or darker than normal; there may be blotchy, uneven areas, patches of brown to gray discoloration or freckling. Skin pigmentation disorders occur because the body produces either too much or too little melanin. Melanin is the pigment produced by melanocyte cells. It is triggered by an enzyme called tyrosinase, which creates the color of skin, eyes, and hair shades.

Melanin has two major forms that combine to create varying skin tones. Eumelanin produces a range of brown skin and hair color, while pheomelanin imparts a yellow to reddish hue.

Melanin provides some amount of sun protection for the skin by absorbing ultraviolet light. Darker skin colors are less susceptible to sunburn and the overall effects of sun damage.

Increased melanin production — also known as hyperpigmentation — is often referred to as melasma, chloasma or solar lentigenes.

• Melasma is a general term describing darkening of the skin.
• Chloasma is generally used to describe skin discolorations caused by hormones. These hormonal changes are usually the result of pregnancy, birth control pills or estrogen replacement therapy.
• Solar lentigenes is the technical term for darkened spots on the skin caused by the sun. Solar refers to sunlight and lentigene describes a darkened area of skin. These spots are quite common in adults with a long history of unprotected sun exposure.

Aside from sun exposure and hormones, hyperpigmentation can be caused by skin damage, such as remnants of blemishes, wounds or rashes.This is especially true for those with darker skin tones.

The most typical cause of darkened areas of skin, brown spots or areas of discoloration is unprotected sun exposure. Once incorrectly referred to as liver spots, these pigment problems are not connected with the liver.

On lighter to medium skin tones, solar lentigenes emerge as small- to medium-sized brown patches of freckling that can grow and accumulate over time on areas of the body that receive the most unprotected sun exposure, such as the back of the hands, forearms, chest, and face. For those with darker skin colors, these discolorations can appear as patches or areas of ashen-gray skin.