(Post 014)
Rock What Your Mama Gave You: The Role of Heritage in Hyper-pigmentation
Education / 09•16•23
As we kick off Hispanic Heritage Month I wanted to highlight how our cultural backgrounds (whether your Latin, Middle-Eastern, Black or Asian) influence variances in our skin. So, what do freckles, melasma, and vitiligo have in common? They’re all variations in skin pigmentation. The reasons for the variations and the reasons they appear are as diverse as the people who experience them, but the bottom line is that irregularities in skin coloration are prevalent across all people groups and ethnicities.
It’s estimated that one in 20 people experience hypopigmentation, or the decreased production of melanin. This can take the form of pityriasis alba, which is a skin condition in which red, scaly patches resolve into areas of lighter skin, or hypomelanosis guttate, which are small and smooth spots that resemble white freckles. It can also be more pronounced, as is usually the case with the autoimmune condition vitiligo, in which the cells that make pigment stop functioning, or the inherited condition albinism, characterized by a low level or the complete absence of melanin production. Side note, we can’t talk about Vitiligo without mentioning Winnie Harlow because she single handedly made having this skin condition a super power, making other people with the condition feel beautiful and I love her for that. Anyway, Hypopigmentation can be experienced by anyone, but it’s generally more noticeable in people with darker skin.
Hyperpigmentation is the opposite and can take many different forms, ranging from freckles and birthmarks to lentigo and melasma. Because hyperpigmentation is caused by an increase in melanin production, people with darker skin are naturally more prone to dark spots because melanocytes are producing more melanin to begin with. While lentigo, also known as age spots, is usually attributed to prolonged sun exposure, and birthmarks are caused by incorrectly formed blood cells or the overgrowth of melanocytes during a baby’s development in the womb, freckles and melasma may be influenced by genetics. But just how is hyperpigmentation passed down from one generation to the next?
Let’s start at the beginning. Our skin tones are the result of the production of melanin by melanocytes, which are found in the base layer of the epidermis, or outer layer of skin. Melanocytes contain organelles (structures inside cells that perform a specific function) called melanosomes, which are responsible for the synthesis and storage of melanin. There are at least five kinds of melanin, but eumelanin and pheomelanin are the two that play the biggest role in determining skin tone. Eumelanin is brown and black, and provides natural protection from UV rays. Pheomelanin is yellow and red, and doesn’t offer any barrier from the damage UV rays can cause. I know that all sounds super scientific so I’ve enlisted Chat GPT to help break it down.
- Our skin color is determined by something called melanin.
- Melanin is like a coloring agent in our skin.
- Melanin is made by special cells called melanocytes.
- Think of melanocytes as the paint factories in our skin.
- These melanocytes are located in the bottom layer of our outer skin (the epidermis).
- Imagine this layer as the bottom of a wall where we're painting.
- Inside melanocytes, there are tiny structures called melanosomes.
- Think of melanosomes as little containers where melanin is made and stored.
- There are different types of melanin, but two of them matter most for our skin color: eumelanin and pheomelanin.
- Eumelanin is like brown and black paint. It's good because it helps protect our skin from the sun.
- Pheomelanin is like yellow and red paint. But unlike eumelanin, it doesn't protect our skin from the harmful effects of the sun.
So, our skin color depends on how much of these two “paints” (eumelanin and phemelanin) we have and where they’re located in our skin.
And now here is where Heritage comes into play. The amount of melanin stored in our skin decides our skin tone, but what determines how much melanin is stored in our skin? That’s where genetics come in. There are over 125 genes that influence skin pigmentation, from the amount of melanin produced to the survival and function of skin cells. These genes are passed on from parents to children and expressed according to gene dominance.
The variations we see in our skin tones today may reflect evolutionary adaptations that took place at the genetic level to allow our ancestors to survive in both warm regions with long daylight hours and cold regions with shorter daylight hours. Eumelanin in the epidermis protects the dermis and subcutaneous tissue from UV damage, while pheomelanin allows sunlight to permeate the skin layer so that the body can efficiently produce vitamin D.
Genes “set” the number of melanocytes we have, but other factors like sun exposure and inflammation can trigger an increase in melasma production. That’s why darker skin tones don’t grow lighter in the absence of sunlight, but tans can fade and hyperpigmentation can diminish in appearance. It may also explain why melasma may be traceable throughout a person’s family tree, but still increase in visibility after prolonged sunlight exposure or during pregnancy. The predisposition for hyperpigmentation is inherited, but other variables can also play a role in its development.
Getting nerdy again, in studying the genetics of pigmentation irregularities, which are easily visible, scientists have gained a greater understanding of the roles of genes that present less obviously. Similarities between melanocytes and other cell types have led to discoveries of shared genetic pathways. These new findings perpetuate the interest in the science of human pigmentation, by pointing to how much we still don’t understand about genetics and the incredible functions of the human body!
The more scientists uncover about the complex workings of melanin production, the more specifically they’ll be able to pinpoint the causes of different kinds of hyperpigmentation. Being able to identify the genes and other factors involved in an increase in melanin production would open the door to the development of safe and effective ways to address the underlying causes. And if that helps to encourage greater health and wellness for people of all skin tones, then we’re all about it!
https://www.dermascope.com/fact-or-fiction/11476-is-hyperpigmentation-genetic
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3694277/
https://www.karger.com/Article/Abstract/468538
https://eudelo.com/2019/08/20/white-freckles-arms/
https://www.ncbi.nlm.nih.gov/books/NBK563245/
