Melasma: Causes, Mechanism, and Diagnosis

Melasma is a common skin condition, often occurring in women. Here is detailed information about the etiology, mechanism, and diagnostic methods of melasma:

Etiology:

• Gender: Females have a higher risk of developing melasma than males.

• Genetics: Family history of melasma is also a risk factor.

• Hormones:

• Pregnancy: Increased estrogen levels during pregnancy can stimulate melanin production, leading to melasma.

• Oral contraceptives: Birth control pills containing estrogen can also cause melasma.

• Hormonal imbalances: Thyroid disorders, ovarian dysfunction can affect hormone production and cause melasma.

• Chemicals, oils: Frequent exposure to chemicals and oils in cosmetics or the work environment can irritate the skin and lead to melasma.

Mechanism:

The female hormone estrogen affects melanocytes, stimulating the overproduction of melanin. Melanin is a natural pigment in the skin that protects it from UV rays. However, excessive melanin production leads to melasma.

Diagnosis:

Clinical:

• Patients often exhibit hyperpigmented patches that are not itchy, burning, or scaly.

• Common locations: cheeks, temples, chin, nose.

• Color:

• Epidermis: brown, tan.

• Dermis: blue, black.

Paraclinical:

• Skin biopsy (MBH): Dense deposition of melanin granules in the epidermis, melanocytes proliferate with dendritic processes, normal epidermal thickness.

• Wood’s lamp: Helps accurately identify the location and severity of melasma.

• Hormone levels: Helps determine the cause of melasma due to hormonal imbalances.

Note: The diagnosis of melasma should be based on a combination of clinical and paraclinical findings to determine the most effective treatment method.