What is hyperpigmentation?

Skin pigmentation, which refers to the amount of melanin produced by the body, determines skin color.

There are 2 main types of melanin, both produced by melanocytes in the epidermis: pheomelanin and eumelanin. Pheomelanin gives lighter skin tones, while eumelanin is responsible for darker skin tones.

Eumelanin acts as a sunscreen because it absorbs the sun's UV rays and protects the skin from sunburn. Studies have shown that people with high levels of eumelanin have a lower risk of developing skin cancers than those with low levels.

What causes skin pigmentation?

Skin pigmentation is a complex phenomenon resulting from the interaction between genetic and environmental factors.

• Genetics

Genetics play a fundamental role in determining skin pigmentation, as genes passed down from parents influence how melanocytes produce and distribute melanin in the skin.

• Sun exposure

Sun exposure is a major external factor that influences skin pigmentation. 

To protect itself from UV rays, the skin produces more melanin, which leads to tanning and can cause long-term changes in skin pigmentation.

• Hormones

Hormonal changes, such as those occurring during pregnancy, can also influence skin pigmentation. A common example is the "mask of pregnancy," where specific areas of the face may become darker due to hormonal fluctuations.

• Certain medications

Several medications can also lighten skin pigmentation. One class of drugs, antibiotics, can stimulate melanin synthesis, thereby increasing skin color. When certain medications, such as birth control pills, are taken together, skin pigmentation can also intensify. A person taking medication should consult their doctor to find out if the medication could impact their skin color.

What is hyperpigmentation?

Hyperpigmentation is an overproduction of melanin by the epidermis, which can lead to various skin changes.

What are the different types of hyperpigmentation?

• Age Spots

Also known as liver spots or solar lentigines, these are flat, brown spots that typically appear on areas of the skin exposed to the sun, such as the face, hands, and décolletage.

• Pregnancy Mask, also known as melasma

Melasma is recognized by larger spots, often on the face, which can vary in color from light brown to dark brown.

This type of hyperpigmentation is caused by hormonal fluctuations. Progesterone and estrogen can stimulate melanin production, which then leads to the appearance of spots. Sun exposure is a major aggravating factor for melasma. Ultraviolet rays stimulate melanin production, and prolonged exposure can intensify irregular pigmentation.

Additionally, there is a racial component. Melasma is more common in people with darker skin, especially those of Asian, Mediterranean, Hispanic, or African descent.

Furthermore, certain cosmetic products, as well as the frequent use of perfumes, can trigger or worsen melasma, especially when combined with sun exposure.

• Post-Inflammatory Hyperpigmentation

Post-inflammatory hyperpigmentation refers to darker spots that appear after a skin lesion, such as acne or an injury, has healed, and are the result of the scarring process following skin inflammation.

The healing process involves a series of complex cellular events that can affect melanin production.

Cytokines, which are signaling molecules released during inflammation, can stimulate the activity of melanocytes, leading to excessive melanin production in the affected area.

Melanocytes can also be activated to produce more melanin to protect the new skin forming. This can result in darker pigmentation on the scarred area.

The duration of the skin's healing process can also influence the final pigmentation. The longer the healing takes, the greater the chance of observing darker pigmentation.

• Freckles, also known as ephelides

These are flat spots, often lighter than the natural skin color and of genetic origin. Feel free to read our dedicated article to learn more.

• Sun Spots or Actinic Lentigines

Actinic lentigines are flat, well-defined brown spots that form on the skin due to prolonged exposure to the sun's ultraviolet rays. They typically appear on areas frequently exposed to the sun, such as the face, hands, and décolletage, and are the result of accumulated sun damage over time. These spots, often called sun spots, are primarily observed in people who have had significant sun exposure throughout their lives.

• Pigmented Birthmarks (Nevus)

Pigmented birthmarks, also known as nevi, appear as pigmented marks on the skin, ranging from light brown to black. Recognizable by their often round or oval appearance, these dark spots can vary in size and shape. Their location on the skin can be diverse, and they generally result from genetic factors and embryonic development. These pigmented birthmarks can be present from birth or appear later in life, sometimes evolving in size and color over time. While most nevi are harmless, some may require medical monitoring, especially if they show unusual changes.

• Drug-Induced Hyperpigmentation

Drug-induced hyperpigmentation appears as excessive skin discoloration, usually brownish or grayish, caused by certain medications. This pigmentation can appear diffusely on various body parts and is specific to an individual's reaction to the medication. Some medications, such as antibiotics or oral contraceptives, have been linked to this type of skin side effect.

• Vitiligo

Vitiligo is characterized by areas of skin that lose their pigmentation, creating white or discolored patches. Identifiable by their depigmented appearance, these patches can vary in size and shape, and are often more noticeable on darker skin tones. Vitiligo results from the destruction of melanocytes, the cells responsible for producing melanin, although the exact cause is not fully understood. Genetic, autoimmune, and environmental factors are often associated with this skin condition. While vitiligo is not physically harmful, it can have a psychological impact, and treatment options generally aim to reduce the appearance of the patches or restore pigmentation.

 

Sources

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