Melasma is also known as Chloasma, or the
pregnancy mask. This form of hyperpigmentation is a tan or dark skin discoloration that looks symmetrical on both sides of the face with an irregular border.
Melasma is thought to be caused by sun exposure, genetic predisposition, hormone changes, and skin irritation. Although it can affect anyone, melasma is particularly common in women, especially pregnant women and those who are taking contraceptives or hormone replacement therapy (HRT) medications.
The cause of melasma is complex. The pigmentation is due to overproduction of melanin deposited in the dermis. There is a genetic predisposition to melasma, with at least one-third of patients reporting other family members to be affected. In most people, melasma is a chronic disorder.
Known triggers for melasma include:
Sun exposure and sun damage: this is the most important avoidable risk factor. Visible light and ultraviolet rays contribute to abnormal pigmentation.
Pregnancy: the pigment often fades a few months after delivery.
Hormone treatments: oral contraceptive pills containing oestrogen and progesterone, hormone replacement, and implants are a factor in about a quarter of affected women, scented soaps, cosmetics may cause a phototoxic reaction that triggers melasma due to artificial fragrances and ingredients.
Melasma presents as freckles like spots and larger flat brown patches. These are found on both sides of the face and have an irregular border. There are several distinct patterns.
Centro facial pattern: forehead, cheeks, nose and upper lips
Malar pattern: cheeks and nose
Lateral cheek pattern
Mandibular pattern: jawline
Poikiloderma: reddened, photoaging changes are seen on the sides of the neck,
mostly affecting patients older than 50 years.
Brachial type of melasma affecting shoulders and upper arms