The Pigment Cycle: How a Spot Forms

Hyperpigmentation is a common skin condition that occurs when more than normal amounts of melanin are produced, leading to dark pigmentation in the skin. “Hyperpigmentation is an overproduction of melanin caused by either the sun, hormones or an inflammatory response,” says Reston, VA, dermatologist Dr. Syed Amiry. The sun is the main culprit of hyperpigmentation. But hormonal changes or a reaction to an injury endured by the skin (inflammation), like acne, eczema or even a cut or burn, can cause discoloration.

All skin types are prone to hyperpigmentation. “Hyperpigmentation is more common in darker skin because naturally there’s more melanin and more melanocytes that can respond in an aggressive manner,” says Dr. Amiry. When dark skin experiences discoloration, it appears as dark black or brown spots or patches. Lighter skin tones, which have fewer or less active melanocytes, see more red and pink spots and patches.

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:

1. A trigger sends a signal to the melanin stimulating hormones. After this message is sent, the enzyme tyrosinase is activated.

2. Once tyrosinase is signaled, the melanocyte cell receives a message to produce pigment (melanin). The melanocytes make melanin and package them into little bundles known as melanosomes.

3. The cell disperses the pigment upward through the dermis, resulting in hyperpigmenation. Because the body can’t divvy up the pigment properly, it gets deposited in clumps that show as spots and discoloration.

4. Permanent pigmentation. 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.


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