How Hyperpigmentation Happens

The majority of cells in the epidermis are skin cells, which create a protective layer. But about every eighth cell is a melanocyte cell, which makes melanin. Melanin is produced in the lower levels of the skin, and the pigmentation process resembles that of an assembly line.

First a trigger-the sun, inflammation, injury or hormones-sends a signal to the melanin-stimulating hormones. After this message is sent, the enzyme tyrosinase is activated. Once tyrosinase is signaled, the melanocyte cell receives a message to produce pigment. The melanocytes make melanin and package them into little bundles known as melanosomes. The cells then disperse pigment upward through the dermis, resulting in hyperpigmentation.

Because the body can't divvy up the pigment properly, it gets deposited in clumps that show up as spots and discoloration. As the skin ages, the cycle is less controlled (sun exposure and hormonal changes interrupt it), and the steady distribution of melanin becomes more diffuse. As excess melanin is produced, hyperpigmentation forms, creating deposits of color that stay indefinitely unless treated.

From around the web