Hyperpigmentation of the skin: imperfections and hyperpigmentation disorders

Freckles

Determined by genetic factors, freckles are hyperchromies in the form of a small pigmented spot, dark in color and circular in shape.

Freckles appear on the face, neck, shoulders, trunk and back of the hands, especially in individuals with very light skin (phototype I and II), with blond or red hair. Similar to the freckles, they differ in the darker color (brown or black); may increase in number after prolonged exposure to sunlight, which further activates the melanocytes.

Following repeated irritative stimuli or degenerative phenomena related to old age, freckles can present morphological changes (increase in volume, surface irregularity).

The freckles

The freckles, also of a genetic nature, are very similar to freckles, but they have a different nature. First of all they are much more sensitive to solar radiation, so they appear mainly in the summer season and mainly on the exposed areas (face, neck, hands). They appear as small patches of light-red brown that form, especially in people with light or red hair, due to an alteration of melanocytes and oxidative processes induced by UV rays. Unlike freckles, they become more noticeable after being exposed to the sun, so adequate sun protection can help reduce them.

Solar lentigo

The solar lentigo appear as patches of irregular shape and variable size, whose color can go from yellow to brown. They occur mainly on the areas most exposed to solar radiation and are caused by excessive exposure to the sun without adequate protection, with consequent burns. This phenomenon most frequently affects people from 45-50 upwards, whose skin has a slower cell turnover. It is possible to prevent this type of hyperpigmentation through correct exposure to the sun, avoiding all the conditions that lead to a burn.

Lentigo senili

The senile lentigo, unlike the solar ones, are due to the sum of the damages caused by the sun exposure over time. They appear as brown macular lesions, generally 1 cm in diameter, and are more common in men than in women. The most typically affected areas are the most exposed areas: the face and the back of the hand. They are rarely seen in patients under the age of 50. Since they can lead to more dangerous pathologies, such as melanoma or basal cell carcinoma, it would be advisable to prevent this risk by using creams containing sun filters.

Melasma

Melasma, or chloasma gravidarum, is linked to an irregular and intense accumulation of melanin, not accompanied by proliferation of melanocytes, but by an overproduction of the pigment itself.

It appears through blocks of irregularly shaped pigments, characterized by a color ranging from light brown to dark brown, which are mainly located on the central part of the face, but sometimes also on the neck, forearms and less exposed areas such as the thorax and perigenital areas .

However, three main melasma distribution areas can be recognized:

• Facial center area, which includes nose, forehead, cheeks, upper lip and chin
• Cheeks and nose
• Mandibular area (less common)

Melasma is also called chloasma gravidarum because it appears very often in pregnancy or when taking the contraceptive pill. It affects brown women and dark-skinned women with greater incidence. The causes of this phenomenon are not yet clearly defined, but the action of estrogen and sun exposure play an important role. The appearance of the spots, in fact, seems to be correlated to the hormonal levels, in particular to 17-β estradiol, responsible for a significant increase in tyrosinase activity. Melasma is also more widespread in the summer months than in the winter months, demonstrating that sun exposure is one of the main causes responsible for the appearance of this phenomenon. A genetic predisposition, stress, the use of some drugs, ovulation disorders and allergic reactions due to the use of cosmetics can help trigger or worsen this pigmentation disorder. Melasma can improve with lightening creams, peelings and lasers, but sometimes it tends to reform itself for several years after the first event.

Freckles from "tanning bed"

They present themselves as melanocytic lesions that occur after exposure to UV rays from the sun beds. Although they resemble solar freckles, from a histological point of view they have revealed a melanocytic hyperplasia that can determine the appearance of skin cancer.1

Post-inflammatory hyperpigmentation

Post-inflammatory hyperpigmentation (PIPA) occurs in the form of a dark pigmentation that surrounds a previously inflamed area. It may be the result of several skin disorders. It is common in individuals with darker skin types and can appear in any part of the body, making it particularly detrimental in patients whose face is affected. This pathology can be the result of various skin events (acne, eczema, folliculitis, burns, scars) or treatments such as peeling or laser.