Explanation of the causes and symptoms of "blemishes and freckles"

<Things you should know> Correct knowledge about "blemishes and freckles" (1) Explanation of the causes and symptoms of "blemishes and freckles"

What are blemishes and freckles?
Main types of blemishes (symptoms)
About the mechanism of blemishes and freckles
Main causes (factors) of blemishes and freckles
Diseases (medical names) that resemble blemishes and freckles

Freckles and age spots, once they appear, are notoriously difficult to get rid of. While their number tends to increase with age, many people suffer from them from childhood. Although the effects of ultraviolet rays are often highlighted, there are actually various causes of freckles and age spots. We'll explain in detail, supervised by a dermatologist.

What are blemishes and freckles?

While "blemishes and freckles" are often discussed together, do you know the difference between them? Let's start by explaining what they are and their characteristics, which trouble many women.

Glossary

The true nature of blemishes and freckles is the excessive accumulation of melanin pigment in the epidermis. Melanin pigment, which determines the darkness of the skin, makes the skin darker the more it is present.
"Spots" are thought to be caused by a combination of genetic factors, hormonal influences, and ultraviolet radiation, and it's not uncommon for them to appear during pregnancy. On the other hand, "freckles," unlike spots that develop later in life, are highly hereditary and are more common in people with fair skin.

The difference between blemishes and freckles

Freckles and age spots differ in how they develop and can be distinguished by their location and shape. Age spots often appear in small areas, and are particularly common on the forehead, cheeks, and in front of the ears. They are pigmented spots that come in various colors, shapes, and sizes, and while their shape is irregular, their borders are clearly defined.
Freckles are small, irregularly shaped, light brown to dark brown pigment spots, 1-5 mm in diameter, that appear frequently on the face, hands, arms, shoulders, and back. They develop after the age of three due to the activation of melanocytes and become more noticeable during puberty.

Main types of blemishes (symptoms)

Even though we refer to them simply as "blemishes," there are many different types. Let's take a look at the main types and their symptoms.

Freckles (ephelides)

As mentioned above, these are small pigmented spots that appear frequently on exposed areas such as the face, arms, shoulders, and back. They typically develop in early childhood, after the age of three, and become more pronounced during adolescence.
Senile pigment spots

These spots occur when epidermal cells damaged by ultraviolet radiation continue to stimulate melanocytes, leading to increased melanin production. They are light brown to dark brown in color and are most common in sun-exposed areas such as the cheeks. The main cause is thought to be keratinocytes (epidermal cells) with genetic abnormalities that send abnormal signals for melanin production. Therefore, even if there is no abnormality in the melanocytes, excessive melanin production occurs, resulting in the formation of spots.
Melasma

Melasma is a common type of skin discoloration. It appears symmetrically on the forehead, sides of the forehead, above the eyebrows, cheeks, and cheekbones in women over 30, and is overwhelmingly more common in women. It is characterized by brownish pigment spots that resemble the pattern on the surface of the liver. It naturally fades after the age of 60.
Post-inflammatory hyperpigmentation

This condition occurs when inflammation caused by acne, insect bites, friction, burns, etc., releases inflammatory cytokines that trigger melanin production, resulting in hyperpigmentation in the affected area. A characteristic feature is that hyperpigmentation occurs after the inflammation subsides. It will naturally fade away by normalizing the skin's turnover cycle.
Seborrheic keratosis

Appears in almost everyone after middle age. It is caused by an abnormality in the genes of keratinocytes (epidermal cells), which leads to excessive cell proliferation. Some start as raised areas that are the same color as normal skin, while others begin as flat pigmented spots that gradually become raised and form brownish to black nodules (lumps). If the brownish color is strong, it is important to distinguish it from malignant tumors such as basal cell carcinoma or melanoma.

About the mechanism of blemishes and freckles

Spots and freckles cast a dark shadow on a woman's skin. But how exactly do they form?

When the skin is exposed to stimuli such as ultraviolet rays, it begins to produce melanin. The raw material for melanin pigment is a substance called tyrosine. Tyrosine is used in melanocytes with the help of the oxidizing enzyme tyrosinase to produce melanin pigment.

When the genes of keratinocytes become abnormal due to the accumulation of ultraviolet rays that we are exposed to since childhood, melanocytes will produce too much melanin pigment even if they are functioning normally.

Melanin is one of the factors that determine our skin color. There are two types of melanin: eumelanin, which is a dark brown pigment, and pheomelanin, which is a yellow or red pigment. A high ratio of eumelanin results in darker skin and hair, while a high ratio of pheomelanin results in lighter skin and blonde hair. What is generally referred to as melanin is actually a mixture of eumelanin and pheomelanin.

Melanin pigment increases in quantity within granular melanosomes, and once a certain amount is reached, the melanosomes are transferred to keratinocytes (epidermal keratinocytes: mainly basal cells). In this way, our skin color darkens as melanin is produced and moves to the upper layers of the epidermis.

Melanin pigment, which darkens skin color, is normally expelled through cell turnover. However, it can accumulate due to dysfunction of epidermal and dermal cells, or disruptions or declines in metabolism. This pigmentation is what we call freckles and age spots.

Main causes (factors) of blemishes and freckles

Ultraviolet rays are the biggest enemy of blemishes and freckles. When it comes to preventing blemishes, we tend to focus only on sunscreen, but there are actually several other possible causes. Let's look at the main causes for each symptom.

Freckles (ephelides)

Because it is caused by genetic factors, it differs from blemishes that develop later in life. Generally, it is seen in people with fair skin who tan easily, and is said to be less common in people of East Asian descent, including Japanese people. It is particularly common in Caucasians, blondes, and people with red hair.
Senile pigment spots

It is believed that the main cause is that keratinocytes (epidermal cells) with genetic abnormalities send abnormal signals to stimulate melanin production, and these spots appear in areas that are easily exposed to ultraviolet (UV) light. They are acquired age spots and generally appear after middle age, but in many Japanese people, they start appearing around the age of 20 as a result of the accumulation of exposure to a lot of UV light from childhood.
Melasma

Genetic factors, the influence of sex hormones, ultraviolet radiation, pregnancy, and endocrine disorders are thought to be involved. Hormonal abnormalities are often involved, and the condition worsens with ultraviolet radiation.
Post-inflammatory hyperpigmentation

It can be caused by inflammation from acne, insect bites, burns, etc. It is often seen after inflammation caused by scrubbing with a nylon towel or scratching. In some cases, allergic contact dermatitis occurs after contact with an allergen, and hyperpigmentation occurs after the rash subsides.
Seborrheic keratosis

It is said that these spots increase with age, and recent research has revealed that gene mutations may be involved in their development. However, unlike senile lentigines, which also involve gene mutations, they do not necessarily involve melanin production. They appear like age spots because the stratum corneum thickens due to cell proliferation, making them appear darker than the surrounding skin.

Genetic factors, hormonal imbalances, and UV radiation are often cited as contributing factors, but stress is also believed to accelerate the formation of age spots. There is a close relationship between pigment cells and the nervous system, and some theories suggest that an unstable mental state makes one more prone to developing age spots. Stress, lack of sleep, and overwork are also factors that generate reactive oxygen species, which promote aging, and these reactive oxygen species can cause gene mutations. In order to prevent an increase in age spots, it is important to maintain a stable daily life.

Diseases (medical names) that resemble blemishes and freckles

It's not uncommon for what people think are freckles or age spots to actually be a different condition. To ensure proper care, it's important to know what other conditions resemble freckles and age spots.

Female facial melanosis

This primarily refers to hyperpigmentation caused by cosmetics. It is a condition that develops gradually after repeated allergic reactions. The affected area is a reddish-brown color, and is accompanied by characteristic inflammation such as itching and a burning sensation.
Malignant melanoma

Malignant tumors that develop when melanocytes become cancerous. They are known to metastasize easily and are difficult to treat. They often develop in adulthood and are characterized by very dark spots, asymmetrical and irregular shapes, and uneven color. They grow gradually over about 10 years and are accompanied by pain. Malignant tumors have an increased vascular component, so redness may also occur.
Bowen's disease

It is characterized by being round to oval-shaped and moist. The exact cause is unknown, but it has been confirmed that it is caused by arsenic exposure.

Supervised by: Dr. Masamitsu Ichihashi, Director of Arts Ginza Clinic
After graduating from Kobe Medical University, he studied at the Institute of Dermatology, University of London. After serving as a professor at Kobe University School of Medicine and director of the Regenerative Future Clinic Kobe, he opened Arts Ginza Clinic, which specializes in regenerative medicine. He is an honorary member of the Japanese Dermatological Association, a member of the Japanese Society for Investigative Dermatology, a board member of the Japanese Society for Pigmented Cells, and an auditor of the Japanese Society of Anti-Aging Medicine, among other academic activities.

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