How does genetics affect the way we form pigmentation?
We all have unique eyes, hair and skin. This is all thanks to melanin, a natural skin pigment that gives us our colour. In our lifetime, our skin can become darker or lighter depending on our body’s production of melanin. A myriad of factors can cause this change of production, such as genetics, sun exposure or skin damage. In this article, I will explain the role of genetics in pigmentation, factors that trigger pigmentation shifts and pigmentation removal options.
How pigmentation is formed
So you took a walk under the sun and came back a shade darker. Did you know the change in skin tone was through a complex process in which cells in the outer layer of your skin (also known as melanocytes) produce melanin? Inside these cells are melanosomes, an organelle found in humans and animals to absorb and transport melanin. These tiny melanosomes are what cause variations in our skin colour.
Broadly speaking, there are two types of melanin:
Eumelanin is a dark pigment that’s brown and black in colour; hence predominantly found in black and brunette hair. Eumelanin protects your skin by limiting or blocking the amount of harmful UV rays that can damage your cells and lead to health conditions like cancer. It’s also what causes sun tans.
Pheomelanin is a lighter pigment that’s red and yellow in colour. Unlike eumelanin, Pheomelanin does not really protect us from UV rays and actually support the production of cancer causing cells or reactive oxygen radicals.
Depending on whether you have more eumelanin or pheomelanin, your skin colour or pigmentation will be affected. For example, more pheomelanin gives rise to red hair and freckles, which explains the link between redheads and freckles as they carry more variations of the MC1R gene. This group of people generally have a lower concentration of photo protective melanin (eumelanin), which makes them more susceptible to melanoma. Again, this explains why redheads are at a higher risk than the general population for skin cancer; they make up 16% of the world’s melanoma cases.
What causes the shift in pigmentation?
There are over 125 genes that affect skin pigmentation. Together with hormones, genes help regulate the melanin production process. In fact, our genes can control how much eumelanin and pheomelanin your skin cells produce. This is what causes shifts in our skin colour over time. Through research studies, we believe that variations in pigmentation are what helped our ancestors survive a million years ago, as dark skin and light skin came with different benefits. For example, dark skin helped protect people from UV damage, while light skin helped people produce vitamin D more efficiently. As evolution evolved, all these still hold true now.
2. Pigmentation disorders
You might have noticed that what used to be an acne spot is now a darker patch. This is a result of hyperpigmentation, a condition which causes skin to be darker due to higher levels of melanin in the skin. Hyperpigmentation is usually caused by:
- Acne scars
- Age spots and sun spots
- Birth control pills and antibiotics
- Side effect/burning from laser therapy, light therapy or cryotherapy
On the other end of the spectrum, there’s also hypopigmentation, a condition where skin is lighter due to lower levels of melanin in the skin. Hypopigmentation can be caused by:
- Skin injuries like blisters, ulcers, burns, infections or chemical exposure
- Skin conditions like eczema and psoriasis
- Albinism, a genetic condition caused by the lack of a melanin-producing enzyme
Do not confuse hypopigmentation with vitiligo, an autoimmune disorder in which pigment-producing cells are damaged. Unlike hypopigmentation, vitiligo is characterised by smooth, milky white patches all over the body and cannot be treated. High fashion model Winnie Harlow and the late Michael Jackson are some popular celebrities with the condition.
Pigmentation treatment in Singapore
First things first; you want to avoid the thing that caused your pigmentation to begin with. For many of my patients, the number one cause is sun exposure. Realistically, it’s almost impossible to avoid any sun at all in Singapore; so the next best thing we should do is to load up on sunscreen.
There are many types of treatments for hyperpigmentation, with the most common being topical medications like hydroquinone. However, for more severe pigmentation, unfortunately just topical medication alone won’t cut it. Chemical peels and laser therapy might be a better addition. I use the Discovery Pico Laser and Fractional Thulium Laser and have seen fantastic results thus far on my patients.
Hypopigmentation from skin injuries and infections tend to resolve on their own till the underlying infection is cleared. This can take anywhere from weeks to months.
I hope this article shed some light on how pigmentation occurs in our body. We only have one body, let’s take care of it!
- Pavan, W. J., & Sturm, R. A. (2019). The Genetics of Human Skin and Hair Pigmentation. Annual review of genomics and human genetics, 20, 41–72. https://doi.org/10.1146/annurev-genom-083118-015230
- Norton, H. L., Edwards, M., Krithika, S., Johnson, M., Werren, E. A., & Parra, E. J. (2016). Quantitative assessment of skin, hair, and iris variation in a diverse sample of individuals and associated genetic variation. American journal of physical anthropology, 160(4), 570–581. https://doi.org/10.1002/ajpa.22861