Melasma is a common skin condition characterized by the appearance of dark spots on the face, especially on sun-exposed areas such as the forehead, cheeks, upper lip , and chin.
What is melasma?
Melasma, also known as the " mask of pregnancy " when it occurs in pregnant women , is hyperpigmentation of the skin resulting from increased production of melanin .
What is melanin?
Melanin is a fundamental biological pigment that plays a crucial role in determining the color of skin, hair, and eyes in humans and other animals.
Synthesized by specialized cells called melanocytes, melanin is found primarily in the epidermis, the outer layer of the skin.
There are several types of melanin:
- Eumelanin, which is black or brown in color
- Pheomelanin, which is reddish or yellow
Melanin production is triggered by exposure to ultraviolet (UV) rays from the sun, a process that serves to protect the skin from damage caused by these rays.
Melanin absorbs UV rays, minimizing their penetration into deeper layers of the skin and reducing the risk of cell mutations and skin cancer. This protective function explains why people with darker skin, who naturally produce more melanin, are generally less likely to suffer from sunburn and certain types of skin cancer compared to people with lighter skin.
In addition to its protective and aesthetic roles, melanin is also involved in various biological processes, such as hearing and free radical regulation. However, excessive or irregular production of melanin can lead to pigmentary disorders, such as melasma, age spots and post-inflammatory hyperpigmentation, highlighting the importance of this pigment in the health and appearance of the skin.
What causes melasma?
- Exposure to the sun
Sun exposure is the most common cause of melasma. Ultraviolet (UV) rays stimulate melanocytes to produce more melanin, which leads to the appearance of dark spots . Sun protection with regular use of sunscreen is essential to prevent and treat melasma.
2. Hormonal changes
Hormonal fluctuations play a crucial role in the development of melasma. This is why the condition is particularly common in pregnant women and those taking birth control pills . Hormone treatments can also trigger or worsen melasma by increasing melanin production.
In fact, hormones such as estrogen and progesterone can significantly stimulate melanin production.
3. Genetic predisposition
Genetic predisposition is another important factor. People with a family history of melasma are more likely to develop the condition. Ethnic backgrounds can also influence the prevalence of melasma, with people with darker skin being at greater risk.
4. Irritating cosmetic products
Some cosmetic products and skin treatments can irritate the skin and trigger excessive melanin production. It is therefore advisable to use suitable and gentle products for the skin, especially for those who are predisposed to melasma.
What are the different types of melasma?
1. Epidermal melasma
Epidermal melasma is characterized by excessive pigmentation in the superficial layers of the skin, primarily the epidermis. This type of melasma is generally easier to treat because depigmenting agents and topical treatments can better penetrate and target melanocytes in this superficial layer. Characteristics of epidermal melasma include well-defined, dark brown spots that are more visible under ultraviolet light.
2. Dermal melasma
Dermal melasma is characterized by deeper pigmentation, in the dermis, the underlying layer of the skin. This type is often more difficult to treat because topical agents cannot easily reach the melanocytes located in the dermis. Dermal melasma patches typically appear as brownish-gray spots and are less defined. Under ultraviolet light, these patches are not as visible as those of epidermal melasma.
3. Mixed melasma
Mixed melasma combines features of both epidermal and dermal melasma. It manifests as areas of both superficial and deep pigmentation. This type of melasma has a variety of shades, from dark brown to grayish-brown, and is visible under ultraviolet light. Treatment of mixed melasma can be more complex because it requires combined approaches to target both the superficial and deep layers of the skin.
4. Indeterminate melasma
In some cases, the depth of pigmentation cannot be clearly determined by the naked eye or even with the use of specialized devices such as Wood's lamps. This type of melasma is classified as indeterminate until further evaluation can be performed.
How to treat melasma?
Treatment of melasma depends on the type of melasma (epidermal, dermal, mixed) and the severity of the pigment spots. Here are the main approaches used to treat melasma:
1. Sun protection
Sun protection is essential to prevent melasma from worsening. Daily use of a broad-spectrum sunscreen with a high SPF (SPF 30 or higher) helps reduce exposure to UV rays, which can stimulate melanin production and darken existing spots.
2. Topical treatments
-
Hydroquinone: This is the most commonly prescribed depigmenting agent for melasma. It inhibits the enzyme responsible for melanin production. Concentrations vary and may require a prescription.
-
Azelaic Acid: This acid works by inhibiting tyrosinase, an enzyme needed for melanin production. It is often used as an alternative to hydroquinone, especially for sensitive skin.
-
Alpha hydroxy acids (AHAs) and beta hydroxy acids (BHAs) such as salicylic acid : These exfoliating acids can help even out skin tone by removing dead skin cells and stimulating cell turnover.
-
Kojic Acid: Another depigmenting agent that can be used alone or in combination with other ingredients to reduce pigmentation.
3. Chemical peels
Chemical peels, such as glycolic, salicylic, or trichloroacetic acid, can be used to exfoliate the upper layers of the skin, reduce pigmentation, and even out skin tone. They are particularly effective for epidermal melasma.
4. Laser and intense pulsed light (IPL) treatments
Laser and IPL treatments selectively target areas of excessive pigmentation. They can be effective in treating dermal or combination melasma, by breaking up pigment and stimulating cell regeneration. These treatments should be performed by qualified professionals to avoid unwanted side effects.
5. Combination of treatments
In many cases, a combination approach is most effective. For example, using hydroquinone or azelaic acid in the morning, followed by a chemical peel or laser treatment at appropriate intervals, can provide optimal results while minimizing risks to the skin.
6. Avoid triggers
Avoiding factors that can trigger or worsen melasma is also important. This includes not only excessive sun exposure, but also the use of skin-irritating products and stress management, which can influence hormones and worsen melasma.