Melasma

Melasma, also known as chloasma, appears as a blotchy, brownish pigmentation on the face that develops slowly and fades with time. The pigmentation is due to overproduction of melanin by the pigment cells, melanocytes.

What causes melasma?

There is a genetic predisposition to melasma.

Triggers include:

• Pregnancy – the pigment often fades a few months after delivery.
• Hormonal contraceptives, including oral contraceptive pills and injected progesterone
• Sun exposure
• Scented or deodorant soaps, toiletries and cosmetics – a phototoxic reaction
• Unknown factors, when it arises in apparently healthy, normal, non-pregnant wome.

Clinical features

Melasma usually affects women; only one in twenty affected individuals are male. It generally starts between the age of 30 and 40. It is more common in people that tan well or have naturally dark skin compared with those who have fair skin.

Melasma affects the forehead, cheeks and upper lips resulting in macules (freckle-like spots) and larger patches. Occasionally it spreads to involve the sides of the neck, and a similar condition may affect the shoulders and upper arms.

Melasma is sometimes separated into:

Epidermal (skin surface):

• Well-defined border
• Dark brown colour
• Appears more obvious under black light
• Responds well to treatment

Dermal (deeper)

• Ill-defined border
• Light brown colour
• Unchanged under black light
• Responds poorly to treatment

Mixed types:

• Combination of light and brown patches
• Partial improvement with treatment