Skin Spots. Why do some people not have skin spots? Is it genetic?

Dr Gemma Márquez.

Skin spots are one of the most common reasons for consultations. But what are skin spots?

Skin spots are the result of hyperpigmentation, that is, an increase in pigment in the skin. Melanin, produced in cells called melanocytes, is the pigment that gives colour to our skin.

Why do we produce melanin? Ultraviolet rays (UVA) stimulate the production of melanin, which is deposited in the skin in a process known as melanogenesis. Therefore, in summer, the skin tans because it is more exposed to the sun, and tanning is actually one of our skin’s defence mechanisms. The production of melanin is not intended to make us look "tanned" and more attractive, but rather it is the skin's defence against damage that it has suffered.

Melanocytes synthesise melanin inside granules called ’melanosomes’. Within keratinocytes, melanosomes accumulate and are strategically located over the cell nucleus (where the DNA is), functioning as a kind of "umbrella" or "protective shield" to protect the DNA from the harmful effects of solar radiation.

The number of melanocytes is practically the same in all individuals, but their ability to produce melanin varies genetically, which explains the differences in skin colour. In dark skin, melanocytes are more active, so there is a greater number of melanosomes. In addition, the melanosomes are larger and are mainly found as granules, unlike in light skin, where groups of melanosomes are packaged into a single unit. The skin's coloration is also determined by the relative proportions of two types of melanin; "eumelanin", a black-brown pigment that predominates in dark skin, and "pheomelanin", a reddish-yellow pigment that predominates in light skin.

Why do some people have more skin spots than others?

It is important to consider that many factors, both internal and external, influence the appearance of skin spots. Pollution, excessive sun exposure over a lifetime, age, pregnancy, hormonal changes, scars resulting from acne, or genetic predisposition are some of these factors.

It is also important to consider that the lifestyle we lead largely determines the state of our skin. In summary, to prevent the appearance of skin spots, I would recommend protecting ourselves properly from the sun, especially the face and hands, which are the areas exposed to the sun all year round. It has been shown that consuming certain fruits and vegetables that are rich in vitamins and polyphenols, such as nuts and dried fruit, and pulses that are rich in monounsaturated and polyunsaturated fats, has positive effects on skin health. Specifically, the benefits that can be seen in the skin from eating these foods are: improved hydration, reduced hyperpigmentation and erythema (redness and inflammation), increased collagen production, and improved elasticity. All these factors are key in shielding the skin against the harmful effects of the sun.

Age is also an important factor in the appearance of skin spots. As we age, and especially from the age of 40, the appearance of skin spots is common. Over time, the skin's ability to regenerate and repair itself decreases, facilitating the accumulation of melanin in certain areas.

Certain life stages such as pregnancy, endocrine diseases of the thyroid or ovaries, and the use of some medications such as oral contraceptives and antiepileptics can also promote the appearance of skin spots.

The skin has a memory

Exposure to ultraviolet radiation, especially during childhood, will largely determine the state of the skin in the future, as it is a key factor in the appearance of skin spots.

We see patients daily who are concerned about their skin spots and claim to protect themselves well from the sun and lead a healthy lifestyle, but they have forgotten that 20 years ago they constantly exposed themselves to the sun in order to get a tan, with little or no sun protection. The sun is life-giving, and outdoor activities should be enjoyed, especially in a country like ours. But it is very important to educate the population, especially from childhood, in correct photoprotection habits, as children have skin that is more susceptible to the harmful effects of the sun.

My recommendation

When a skin spot appears, it is best to make an appointment with a dermatologist to examine it and assess what type of skin spot it is. Many skin spots will not have an impact on skin health and can be treated effectively, either with depigmenting creams or with medical treatments such as laser or peels. However, others may cause greater skin complications. Therefore, an initial diagnosis by a professional is essential so that appropriate treatment can be started for each type of skin spot.