What causes melasma?

Melasma is a common skin condition characterized by the appearance of dark spots on the face, especially on sun-exposed areas like 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 a form of skin hyperpigmentation caused by increased melanin production.

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 primarily found in the epidermis, the outermost 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 the sun's ultraviolet (UV) rays, a process that helps protect the skin from damage caused by this radiation.

Melanin absorbs UV rays, minimizing their penetration into deeper skin layers 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 prone to sunburn and certain types of skin cancer compared to those with lighter skin.

In addition to its protective and aesthetic roles, melanin is also involved in various biological processes, such as hearing and regulating free radicals. However, excessive or irregular melanin production can lead to pigmentary disorders like melasma, age spots, and post-inflammatory hyperpigmentation, highlighting the pigment's importance for skin health and appearance.

What Are the Causes of Melasma?

1. Sun exposure

Sun exposure is the most common cause of melasma. Ultraviolet (UV) rays stimulate melanocytes to produce more melanin, leading to the appearance of dark spots. Sun protection, including the regular use of sunscreen, is essential for preventing and treating 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.

Indeed, hormones like estrogen and progesterone can significantly stimulate melanin production.

3. Genetic Predisposition

Genetic predisposition is another important factor. Individuals with a family history of melasma are more likely to develop the condition. Ethnic backgrounds can also influence melasma prevalence, with people having darker skin being at higher risk.

4. Irritating Cosmetic Products

Certain cosmetic products and skin treatments can irritate the skin and trigger excessive melanin production. Therefore, it is advisable to use gentle, suitable products, especially for those 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, mainly 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, which is 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 spots generally appear as grayish-brown patches and are less defined. Under ultraviolet light, these spots are not as visible as those of epidermal melasma.

3. Mixed Melasma

Mixed melasma combines the characteristics of both epidermal and dermal melasma. It appears as areas of pigmentation that are both superficial and deep. This type of melasma shows a variety of shades, ranging from dark brown to grayish-brown, and is visible under ultraviolet light. The treatment of mixed melasma can be more complex as it requires combined approaches to target both the superficial and deep layers of the skin.

4. Indeterminate Melasma

In some cases, the depth of the pigmentation cannot be clearly determined with the naked eye or even with specialized devices like Wood's lamps. This type of melasma is classified as indeterminate until further evaluations can be performed.

 

How to treat melasma?

Melasma treatment 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 medical prescription.

• Azelaic Acid: This acid works by inhibiting tyrosinase, an enzyme necessary 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 renewal.

• 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 those with 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 for treating dermal or mixed melasma by breaking down pigments and stimulating cell regeneration. These treatments must be performed by qualified professionals to avoid undesirable side effects.

5. Combination Treatments

In many cases, a combined approach is the 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. Avoiding Triggers

Avoiding factors that can trigger or worsen melasma is also important. This includes not only excessive sun exposure, but also using irritating skin products and managing stress, which can influence hormones and aggravate melasma.