These weeks have been busy with the heat (and we still have summer ahead) and lots of news about solar storms. But with summer comes tanning, and closely related to that is an interesting phenomenon that affects a small percentage of the population: freckles. It’s a well-known facial feature, but its science often goes unnoticed.

Summer spots.
Freckles, technically also known as freckles, are melanin pigmentations. This, as usual, occurs when the skin is exposed to the sun, only in the case of freckles the pigment concentrates in limited areas instead of dispersing throughout the skin, forming small spots.

For this reason, freckles are seen especially in the areas that are most exposed to the sun. They are also associated with the summer months for the same reason. They appear during the months when solar radiation is more intense and disappear when it relaxes.

Babies don’t have freckles.
Freckles, yes, don’t appear until a few years later in our lives. The main reason for this is that the little ones did not receive enough doses of solar radiation for melanin to accumulate in their skin. As they appear, freckles fade with age, but there are those who choose to have them removed medically.

But the appearance of freckles has a lot to do with genetics, so it can be said that babies have the instructions for creating them. There is an inherited factor and it has to do mainly with variants of the MC1R gene, the melanotropin receptor gene. This gene is also linked to skin pigmentation and hair color, but not only people with red hair may have freckles. It’s not even unique to white people.

MC1R is not the only gene associated with the appearance of ephelids. A study in Spain identified more genetic variants linked to the IRF4 gene, such as interferon regulatory factor 4, another gene closely linked to the pigmentation of our skin, hair and eyes. It has also been associated with the appearance of gray hair, i.e. a change in hair color.

Different types of freckles.
There are two types of freckles, although it is difficult to distinguish for those who do not know. Simple ones on one side, round and small; and sunburned freckles that are darker and larger with jagged edges.

How do they affect our health?
As explained in the Spanish Academy of Dermatology and Venereal Diseases, “Freckles are benign lesions: they do not contain a disorder or skin disease. They should generally be considered harmless and only in very rare cases do they turn into skin cancer.

Just because these injuries don’t usually lead to more serious problems doesn’t mean that protection and vigilance against serious injuries and skin cancers need to be relaxed. In Spain, melanoma affects about one in 10,000 people, and skin cancers cause about a thousand deaths per year, with a slight upward trend in recent years.

lentil.
Ephelids are not the only benign spots that can appear on our skin as a result of the sun. Lentils, yes, differ from freckles in many ways. We are not born with these spots either, but they appear in adulthood and are permanent.

Lentils are usually larger than freckles and appear in more diverse places such as legs (despite sun exposure). Its appearance is less linked to genetics and more linked to sun exposure.

Superficial problem.
Unlike other skin lesions, freckles are primarily a cosmetic issue. Today, we can easily change our digital images without Photoshop using filters found in many applications. But the science behind these algorithms is no more interesting than the science behind this interesting phenomenon of the human body.

Image | Birth of Ike Louie