As a dermatologist with extensive experience in the field of skin disorders, I can provide you with a comprehensive answer regarding the main cause of melasma.

Melasma is a common skin condition characterized by brown or gray-brown patches on the face. The primary cause of melasma is hormonal changes, particularly an increase in the levels of female hormones such as estrogen and progesterone. These hormones stimulate the melanocytes, the cells responsible for producing melanin, which is the pigment that gives color to the skin. When melanocytes become overactive, they produce more melanin, leading to the darkening of certain areas of the skin.

Other factors that can contribute to the development of melasma include:

1. Genetics: A predisposition to melasma may run in families.
2. Sun exposure: Ultraviolet (UV) radiation from the sun can trigger melasma or make existing melasma worse.
3. Certain medications: The use of oral contraceptives or hormone replacement therapy can sometimes lead to melasma.
4. Pregnancy: Melasma is also known as the "mask of pregnancy" because it often develops during this time due to hormonal changes.

It's important to note that melasma is more common in women, but men can also be affected.

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This means birth control pills, pregnancy, and hormone therapy can all trigger melasma. Stress and thyroid disease are also thought to be causes of melasma. Additionally, sun exposure can cause melasma because ultraviolet rays affect the cells that control pigment (melanocytes).read more >>