Above: Image © istockphoto.com/flisk

Did you know? There are two types of freckles. Ephelides are small tanned round spots that appear after increased sun exposure. Solar lentigines are darker, occur in older people, and don’t fade away in the winter. They are the trademark of the Weasley family in the Harry Potter universe. They are sometimes hated and made fun of, but they are also proudly displayed by celebrities like Emma Stone, Lucy Liu, Jensen Ackles, and Josh Hutcherson. Of course, I am talking about freckles.

Sure, they can look cute, but what exactly are they? Are they the same as moles or birthmarks? Not exactly. The flat, tanned spots known as freckles are due to a higher amount of the skin pigment melanin in areas that are frequently exposed to the sun, such as the face, shoulders,and arms. Though they do not exclusively appear in people with lighter skin—for example, Lucy Liu is of Chinese descent and has a fairly dark complexion—freckles are definitely more common in fair-skinned people with red or blonde hair.

Genetic and environmental factors

Did you know? Moles are pigmented spots caused by a higher concentration of pigment-producing cells (melanocytes). Moles can become cancerous (melanoma).You have a higher chance of getting freckles if your parents are freckled. Fair-skinned redheads actually have a variant of the melanocortin-1-receptor (MC1R) gene that is linked to freckles. The MC1R protein regulates skin and hair colour in humans and other mammals, and different people have different forms (alleles) of this polymorphic gene.

Some people have an allele of the MC1R gene that limits the production of eumelanin, a form of the pigment melanin that is responsible for darker skin and hair. This leads to a buildup of pheomelanin, the melanin pigment responsible for red hair and associated with freckles.

The key environmental factor is sun exposure. Natural sunlight emits ultraviolet (UV) rays, which cause pigment-producing cells (melanocytes) to make more melanin in the outer layer of skin (epidermis). In particular, eumelanin causes you to tan and protects you against some of the damaging effects of future exposure. For example, it absorbs UV radiation and prevents cell damage, which can potentially lead to cancer, in deeper layers of the skin.

Unlike tanning, freckling is an uneven distribution of melanin in the skin. People with freckles, who usually also have a lighter skin type, should therefore be more careful to avoid sun exposure, since they have less protective eumelanin. Because having light skin and red hair in very sunny areas would be an evolutionary disadvantage, it is not surprising that freckles mainly appear in people from northern latitudes, such as Ireland and Scotland, where sun exposure is reduced.

Did you know? Unlike some moles, freckles are generally harmless. They are caused by a higher concentration of the pigment melanin, but the number and size of pigment-producing cells (melanocytes) does not change. The link between sunlight and freckles explains why newborns don’t have freckles, which only appear after the first sun exposure. So why aren’t older people completely covered with freckles after years of being in the sun? Your freckles actually fade as you get older because your skin becomes thicker, making your freckles less visible.

If you don’t like your freckles, you probably should avoid the sun and wear sunscreen. If you want to get rid of the ones you already have, options include laser surgery (laser pigment removal), which involves breaking down melanin pigments with lasers. Some people use creams such as hydroquinone or even lemon juice to bleach their skin! But you’re probably better off just accepting your freckles as a unique and attractive trait, just like the celebrities do.

Learn more!

Online resources

Freckles 101 (2015)

Sarah Siddons, HowStuffWorks

Freckles (2014)

Gary W. Cole, MedicineNet.com

Moles, Freckles, and Skin Tags (2014)
WebMD.com

Websites providing general information freckles and other skin lesions, including the different types, how they develop, health considerations and links to additional information.

Freckles: Evolutionary Advantage or ‘Cancer Factories’? (2013)

Nina Jablonski, California Academy of Sciences

Video of an expert on the evolution of skin colour in humans discussing the evolutionary disadvantages associated with the red-haired, light-skinned phenotype.

The melanocortin-1-receptor gene is the major freckle gene (2001)
M. Bastiaens, J. ter Huurne, N. Gruis, W. Bergman, R. Westendorp, B. J. Vermerr, J.-N. Bouwes Bavnick. Human Molecular Genetics 10(16), 1701-1708.

Article exploring the relationship between MC1R gene variants, ephelides and solar lentigines.

Other resources

M. T. Bastiaens, R. G. J. Westendrop, B. J. Vermeer & J. N. Bouwes Bavnick. (1999). Ephelides are more related to pigmentary constitutional host factors than solar lentiges. Pigment Cell & Melanoma Research 12(5), 316-322.

Article exploring the differences between ephelides and solar lentigines. An abstract is available on the publisher’s website. A subscription is required to view the full text.

P. Valverde, E. Healy, I. Jackson, J. L. Rees & A. J. Thody. (1995). Variants of melanocyte-stimulating hormone receptor gene are associated with red hair and fair skin in humans. Nature Genetics 11, 328-330.

Letter discussing how variants of the MC1R gene affect levels of pheomelanin and eumelanin, and how they relate to different pigmentation phenotypes. An excerpt is available on the journal’s website. A subscription is required to view the full text.

K. H. Kaidbey, P. P. Agin, R. M. Sayre & A. M. Kligman. (1979). Photoprotection by melanin—a comparison of black and Caucasian skin. Journal of the American Academy of Dermatology. 1(3), 249-60.

Article discussing the transmission of ultraviolet light through Caucasian and black skin samples, and the role of melatonin in protecting the skin. An abstract is available on the journal’s website. A subscription is required to view the full text.

Anne-Christine Auge

I’m originally from Leipzig, Germany, where I grew up and did my undergraduate degree in Biology, with a specialization in Behavioural Ecology. I’ve always loved travelling and did a few internships and volunteer experiences in various projects involving sea turtles, invasive plants or bats in Mexico, the US and Australia. Wanting to see even more of the world, I decided to start my Master’s degree at Carleton University in Ottawa, Canada in 2012, researching the behaviour of guppies. I am very curious and want to know how the world works, that’s why I love science! In my free time I love photography, walking around in nature, and cooking!  

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