What is Hyperpigmentation?
Understanding how to lighten your pigmentation requires an understanding of how pigmentation is formed in your skin. Here is a brief look at how color/melanin/pigment is formed in the melanocyte cell.
The skin tone that we are born with is first developed by melanocytes. These cells reside in the basal layer of the epidermis (see graphic). The structure of a melanocyte cell is much like an octopus with arm like protrusions called dendrites. One melanocyte cell can provide about 36 keratinocytes that contain melanin.
As melanin is formed, it’s packaged up into unique organelles (tiny structures within the cell) called melanosomes. These packages of melanin are delivered from the melanocyte via the dendrites to the different keratinocytes.
Melanin is pigment formed within the Melanocyte cell, and is the substance that is responsible for the color within our skin, eyes, hair and various other parts of our body. The production of melanin (subject to different stimuli) is the end product that is formed during metabolism of the amino acid Tyrosine.
Two types of melanin are produced by our bodies:
- Eumelanin is brown and black in color. It protects your skin by limiting the amount of harmful ultraviolet (UV) rays that can break through and picking up reactive oxygen radicals which, if left alone, could damage your cells and DNA and potentially lead to chronic health conditions like cancer.
- Pheomelanin, is yellow and red in color. Unlike eumelanin, pheomelanin provides very little protection from UV rays and support the production of reactive oxygen radicals and the damage they cause.
Once a melanosome has reached the keratinocyte, it is released from the dendrite arm to the keratinocyte. This process is referred to as the melanosome transfer.
Types of Dark Spots
Fluctuations in hormones can lead to hyperpigmentation or melasma, a skin condition where hormones cause large dark patches on the cheeks, sometimes the forehead, and the upper lip typically occur during pregnancy and when taking birth control. Estrogen and progesterone, the female sex hormones, stimulate the overproduction of melanin which leads to dark spots. Dark spots due to hormonal fluctuations are more prevalent in darker skin tones. When hormones trigger an increase in this melanin production, you're more susceptible to hyperpigmentation.
While not all hormones can play into different types of hyperpigmentation, Estrogen and Progesterone are the most common.
Another is the melanocyte-stimulating hormone, a collective name for a group of peptide hormones produced by the skin, pituitary gland and hypothalamus. It too can stimulate inflammatory immune response to the cells, which in turn stimulates the melanocyte.
When the body is suffering from prolonged stress, from either illness or daily stress factors, the adrenal corticoid hormones from the adrenal glands become over stimulated. This can result in an over-secretion of cortisol, which may cause hyperpigmentation as well. The receptor sites on the cells get turned on and sent into hyperdrive, resulting in pigmentation that commonly begins along the jaw and outer perimeter of the face.
UV – SUN DAMAGE
Unlike pigment caused by hormones, photoaging or UV damage happens when ultraviolet light from the sun and/or tanning beds permanently damages the skin’s structure.
Ultraviolet radiation causes DNA changes in the skin that can lead to dark spots, skin discolorations, premature aging and skin cancer. There are two kinds of UV light:
Unlike the large, dark patches known as Melasma, small, dark spots of skin known as sun spots, are caused by sun exposure. They commonly appear on skin that is frequently exposed to the sun such as the face, neck, décolleté and hands. Once dark spots have developed, sun exposure can also exacerbate the issue by making then even darker.
Ultraviolet Radiation (UVR) causes cellular damage in the epidermis and results in melanin synthesis in melanocytes and transfer to neighboring keratinocytes, leading to increased skin pigmentation within one day after exposure.
Changes in pigmentation can also be caused by trauma to the skin cells. Generally, when the skin’s immune response is activated, melanocyte activity is also activated. Therefore after experiencing an acne breakout, a cut or a burn, even a bug bite, there may be a small reminder of where it was. When trauma begins to heal, the wound left behind is known as Post Inflammatory Hyperpigmentation (PIH), usually red to light brown in color, it is the easiest of pigment to lighten because it is very much on the surface of the skin and not being triggered by something deep within.
Post Inflammatory Hyperpigmentation (PIH) results from the overproduction of melanin or an irregular dispersion of pigment after cutaneous inflammation. When PIH is confined to the epidermis, there is an increase in the production and transfer of melanin to surrounding keratinocytes.
Amazingly, over 125 genes are known to affect skin pigmentation. Along with hormones, genes are responsible for regulating the melanin production process. The number of melanocytes we have are pre-determined by genetics. However, hyperpigmentation can be increased by UV and tanning beds by increasing and transferring of melanosomes, the organelles that contain melanin.