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 caused by hyperpigmentation, or an increase in pigment in the skin. Melanin, a pigment produced by cells called melanocytes, is responsible for the color of 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. As a result, in the summer, the skin tans more because it is exposed to the sun, and tanning is one of our skin’s defense mechanisms. Melanin production is not intended to make us look “tanned” and more attractive, but rather as the skin’s defense against previous damage.

Melanocytes synthesize 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 in all individuals is nearly identical, but their ability to produce melanin varies genetically, explaining the variations in skin color. Melanocytes are more active in dark skin, resulting in more melanosomes. In addition, the melanosomes are larger and primarily found as granules, as opposed to light skin, which has groups of melanosomes packaged into a single unit. 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), also determine skin coloration.

Why do some people have more skin spots than others?

It is important to note that the appearance of skin spots is influenced by a variety of internal and external factors. Some of these factors include pollution, long-term sun exposure, age, pregnancy, hormonal changes, acne scars, and genetic predisposition.

It is also important to remember that our lifestyle greatly influences the condition of our skin. In summary, to avoid the appearance of skin spots, I recommend that we protect ourselves from the sun, particularly our faces and hands, which are exposed to the sun throughout the year. Consuming fruits and vegetables rich in vitamins and polyphenols, such as nuts and dried fruit, as well as foods high in monounsaturated and polyunsaturated fats, has been shown to improve 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. Skin spots appear more frequently as we age, particularly over the age of 40. Over time, the skin’s ability to regenerate and repair itself decreases, facilitating the accumulation of melanin in certain areas.

Pregnancy, endocrine diseases of the thyroid or ovaries, and the use of certain medications, such as oral contraceptives and antiepileptics, can all contribute to the development of skin spots.

The skin has a memory

Exposure to ultraviolet radiation, particularly during childhood, will have a significant impact on the skin’s future condition, as it is a key factor in the appearance of skin spots.

We see patients every day who are concerned about their skin spots and claim to protect themselves from the sun and live a healthy lifestyle, but they have forgotten that 20 years ago they were constantly exposed to the sun in order to 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 public, particularly children, about proper photoprotection habits, as children's skin is more susceptible to the sun's harmful effects.

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 like laser or peels. However, others may cause greater skin complications. That’s why an initial diagnosis by a professional is essential before appropriate treatment can begin for each type of skin spot.