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 women

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), dermal (deeper) and mixed types.

Treatment

Melasma can be very slow to respond to treatment, so patience is necessary. Start gently, especially if you have sensitive skin. Harsh treatments may result in an irritant contact dermatitis, and this can result in postinflammatory pigmentation.