What Causes Melasma and Who Does It Affect Most?


Melasma is a chronic, acquired hyperpigmentation condition characterized by symmetrical brown patches on the skin. Because it occurs primarily on the face, it is not only a medical condition but also an aesthetic and psychological problem. So, what causes melasma, what risk factors are associated with it, and who does it affect most?

What is Melasma?
The word melasma comes from the Greek root "melas" (black) and refers to the dark brown appearance seen on the skin. While it has been known by various names throughout history (such as "pregnancy mask," "liver spot," and "chloasma"), melasma is currently the most accurate term in dermatological literature.

These symmetrical patches on the skin are particularly noticeable on sun-exposed areas. They are more common in women, especially during periods associated with hormonal changes such as menopause and pregnancy.

Historical Perspective
The first descriptions of melasma date back to the time of Hippocrates. Ancient texts describe skin spots that worsen after sun exposure. Joseph Plenck detailed melasma in the 18th century, dividing it into different clinical forms. Modern medicine began publishing more comprehensive case reports on melasma in the mid-20th century.

Epidemiology of Melasma
Melasma occurs at varying rates in different regions of the world. According to studies:

15–35% of women in Brazil are affected by melasma.

Studies in Iran have found melasma in 39.5% of women.

In India, the prevalence rate has reached 41%, particularly among agricultural workers.

Melasma is also among the most frequently reported pigmentary disorders in countries such as Saudi Arabia and Nepal.

Globally, it is more common in populations of East Asian origin (Japan, Korea, China), the Indian subcontinent, the Middle East, and Mediterranean Africa. This is primarily due to the more pigmented phenotypes and intense sun exposure in these groups.

Which Skin Types Are More At Risk?
Melasma is most commonly observed in individuals with Fitzpatrick skin types III–V. It is rare in lighter skin types (types I–II) or very dark skin types VI.

In a study conducted in Brazil, 34% of patients with melasma had type III, 38% had type IV, and 15% had type V.

Research conducted in Tunisia found that the majority of women with melasma had skin types IV and V.

This suggests that individuals with moderate pigmentation are more prone to melasma.

Why It's More Common in Women
Melasma is reported to be 9–10 times more common in women than in men. Various studies have found this ratio to be 6:1 in India, 39:1 in Brazil, and 21:1 in Singapore.

The main factors that trigger melasma in women are:

Pregnancy (26–51% trigger)

Oral contraceptive use (16–26% associated)

Hormonal fluctuations (menopause, hormone replacement therapy)

In men, the most important risk factors are intense sun exposure and genetic predisposition.

Causes and Risk Factors of Melasma
Melasma has no single cause; its etiology is multifactorial.

1. Sun Exposure
The sun is the most potent trigger. UV rays activate melanocytes, leading to excess pigment production. Therefore, melasma worsens in the summer and subsides in the winter.

2. Hormonal Factors
Increased estrogen and progesterone levels stimulate melanocytes, increasing pigment production.

Although melasma occurring during pregnancy usually disappears after birth, it can persist in some patients.

Oral contraceptive use is also a risk factor.

3. Genetic Predisposition
Approximately half of melasma cases have a family history. The prevalence is particularly high in first-degree relatives.

4. Drugs and Chemicals
Photosensitizers, some cosmetics, and heavy metals can trigger melasma.

5. Stress and Neurological Factors
Stress hormones (ACTH, MSH) can stimulate melanocytes and increase melanin production. Some studies also suggest a link between nerve growth factors and melasma.

Pregnancy and Melasma
Melasma, also known as the "pregnancy mask," is common during pregnancy, especially in the third trimester. Due to hormonal changes, it has been reported that:

Melasma develops in 16% of pregnant women in Iran,

46% in Pakistan, and

37% in Morocco.

It usually disappears within the first year after birth, but in up to 30% of cases, it can leave permanent spots.

Melasma in Men
Although less common, melasma in men cannot be ignored. A study conducted in Puerto Rico found that men accounted for 10% of all cases. Risk factors for men include:

Extended outdoor work (such as construction, agriculture, fishing)

Extensive exposure to sunlight

Family history

Impacts of Melasma on Quality of Life
Melasma is more than just a physical skin problem.