Freckles/Ephelides: An Introduction
Freckles are small brownish marks that are present on the face of some people. They usually appear in sun-exposed areas.
They are mostly harmless and occur due to the overproduction of melanin (the skin pigment) in response to UV stimulation.
There are two categories of freckles, namely ephelides and solar lentigines.
1. Ephelides is the common or characteristic type of freckles. This type of freckles is common in people with light skin and is generally seen in people of Caucasian and Asian descent.
2. On the other hand, solar lentigines are dark patches of skin that include aging spots and sunspots. It tends to appear in older Caucasians (above the age of 40yrs).
Evolutionary Relevance of Freckles
There appears to be an evolutionary purpose of freckles in humans. People who lived in places with higher sun exposure had a darker skin color. This is due to the excess production of melanin, which protects the skin from the harmful effects of ultraviolet radiation (UVR). Lighter-skinned people often have ancestry that evolved with less exposure to sunlight. When they are exposed to greater amounts than usual, excess pigmentation occurs. The geographical location is a major factor in evolution that is linked to the development of freckles.
How Genes Influence The Development of Freckles?
MC1R and Skin Pigmentation
MC1R or melanocortin-1 receptor gene contains instructions for the production of the receptor for Melanocyte Stimulating Hormone (MSH), one of the two hormones that regulate pigmentation. This gene plays an important role in the normal pigmentation process in the body.
Certain changes in the MC1R gene reduce the ability of the MC1R receptor to stimulate eumelanin (pigment responsible for lighter skin) production. This leads to melanocytes making more pheomelanin (pigment for darker skin).
The MC1R receptor is active in cells other than melanocytes as well. These include cells involved in the body’s immune and anti-inflammatory responses.
Several SNPs associated with the MC1R gene are primarily linked to fair skin, red or light hair, and freckles.
They also show a varying risk of melanoma and non-melanoma skin cancers.
rs1805008 and the Tendency To Develop Freckles
rs1805008 is also known as Arg160Trp or R160W. It is one of the many SNPs found in the MC1R gene and is associated with red hair color, especially in the Irish population.
The T allele is associated with increased risk of freckles as well as melanoma. Individuals with TT alleles have an increased probability of developing freckles, 7-10 times more chance of having red hair, and a greater risk of developing melanoma.
TYR Gene and Melanin Production
The TYR gene contains instructions for the production of an enzyme called tyrosinase. This enzyme is involved in the production of the skin pigment melanin. Variations in this interfere with melanin production and, as a result, can cause differences in skin pigmentation.
rs1042602 and the Tendency To Develop Freckles
The rs1042602 SNP on the TYR gene is polymorphic (occurs in different forms) in Europeans. The A allele is associated with [light/fair skin, eye color, and the absence of freckles]
rs1540771 and the Tendency To Develop Freckles
This SNP is found in LOC105374875, which is an uncharacterized RNA gene. The A allele of SNP rs1540771 is said to be associated with a 1.26x risk of freckles, and UV sensitivity, and brown hair.
Non-genetic Influences on Freckles
There are a few non-genetic factors that increase your risk of having freckles.
Increased exposure to UV light
Exposure to ultraviolet light causes the skin cells to produce more melanin. This causes a dark pigmentation on the skin, including darker freckles.
Hormonal treatment
Hormonal treatment like oral birth control can increase the pigmentation by melanin on the skin. The cells that produce melanin, melanocytes, are also stimulated by female sex hormones, estrogen, and progesterone. When these hormone levels change because of treatment, hyperpigmentation occurs.
Recommendations to Remove Freckles
Despite the genetic component, people are not usually born with freckles. So, it is possible to avoid or manage it with a few tips and tricks.
- Use of sunscreen: Sunscreen protects your skin from the harmful effects of the sun and its UV rays. Those who are prone to freckles must apply sunscreen every time they step out. Using a sunscreen of SPF 30 or above can help avoid new freckles but may not help you get rid of the existing ones.
- Laser treatment: There are different types of lasers that target specific areas in the skin.
It can take about 2-3 weeks to recover from the treatment, and more than one session may be required to achieve the desired results. It is important to consult a qualified dermatologist before doing a laser treatment.
- Retinoid cream: Retinoid cream consists of vitamin A which can help lighten the freckles.
The retinoids in the cream help absorb UV-B radiation and prevent the formation of new lesions.
- Cryosurgery: This surgical technique uses extreme cold to destroy abnormal skin cells.
This method can treat or eliminate freckles, but it can have some side effects such as hypopigmentation or blistering.
- Fading Cream: Fading creams are available as OTC products that contain hydroquinone.
The hydroquinone present in these creams suppresses the production of melanin and helps lighten the darkened areas of the skin.
- Using a chemical peel exfoliates the damaged areas of your skin. When the damaged skin heals after a chemical peel, new skin appears without the freckles.
There are also many natural or homemade remedies to lighten or get rid of freckles.
1. Application of lemon juice on the required areas thrice a week can lighten the spots.
2. Homemade scrubs using milk, honey, and oats is another effective method to reduce freckles.
3. Milk products like buttermilk, yogurt, or sour cream have skin light
Summary
- Freckles are mostly harmless, small brownish marks that are present on the face of some people. They usually appear in sun-exposed areas due to the overproduction of melanin under the influence of UV rays.
- The geographical location is a major factor in evolution that is linked to the development of freckles. People who lived in places with higher sun exposure usually have darkly pigmented skin.
- Genes like MCR1 and TYR influence the risk for the development of freckles. Both these genes are studied to influence the pigment distribution in the body.
- Increased exposure to UV light and hormonal treatment are non-genetic influences of developing freckles.
- Creams like sunscreen, retinoid cream, or fading cream can be used to remove freckles. Laser treatment or cryosurgery can also be done to remove freckles.
- Homemade remedies like scrubs using milk, honey, and oats, onions, milk products, and lemon juice can also be used to remove freckles.
References
https://www.wrvo.org/post/what-are-freckles-and-why-do-some-have-more-others#stream/0
https://www.bustle.com/articles/153916-the-science-behind-freckles-is-a-lot-cooler-than-you-thought-video
https://www.healthline.com/health/what-are-freckles#sunburn
https://www.healthline.com/health/melasma#risk-factors-and-causes
