Hyperpigmentation: What is melasma? Causes, symptoms and treatment for the ‘mask of pregnancy’

Melasma is a type of hyperpigmentation that is common in women, especially during and after pregnancy. It normally appears as large dark patches on the face, although other parts of the body can be affected.

Melasma derives from the Greek word for black ('melas'), and it's also referred to as chloasma, as 'cholas' is Greek for green-ish, in pregnant women. This article looks at what causes melasma and how you can reduce the appearance of dark patches on your skin.

Men can experience melasma, but it is much more common in women, with an onset usually between the ages of 20 and 40. Chloasma is common during pregnancy, when up to 50% of women may be affected.

It is more common in people who tan easily, or have naturally darker skin. Melasma is less common in people with fair skin. It typically becomes more visible during the summer, while it improves over the winter months. Though melasma is more common in people with a family history of the condition, it is not thought to be hereditary.

Doctors aren't sure of the exact cause of melasma, but it is thought to develop as a result of pigment-producing cells in the skin (melanocytes) producing too much pigment (melanin).

There are several factors that are associated with the condition, including changes in hormones during pregnancy (chloasma), birth control pills, estrogen and progesterone sensitivity. Sun exposure, stress and thyroid disease are also regarded as causes of melasma.

The sun is a major contributor to, and aggravator of, the development of melasma and other factors such as family predisposition, age and certain anti-epilepsy drugs can also play a role.

There are three types of melasma:

• Epidermal melasma affects the top layer of skin and the hyperpigmentation is brown with well-defined borders.
• Dermal melasma affects the deeper dermal layers of skin and is characterised by blue-grey patches.
• Mixed melasma (a combination of epidermal and dermal) shows as a brown-grey pigment.

You can read more about what causes hyperpigmentation in general and find out more about the different types of the condition in Hyperpigmentation: what causes dark spots and how can I reduce them?

At present there is no cure for melasma, but there are several treatments to improve the skin's appearance. Chloasma may go away a few months after giving birth, though it can come back during another pregnancy.

A combination of measures is generally required for melasma treatment. Year-round, lifelong sun protection is the most significant step you can take to helping to prevent or reduce the severity of melasma.

Limit the time you spend in the sun, keep out of the sun during its most intense hours and wear protective clothing and sunhats whenever possible. This is particularly important if you have a genetic disposition to melasma (i.e. it runs in your family) or if you are pregnant, on the pill or taking another form of hormone supplement. Also, discontinue hormonal contraception if possible.

Dermatologists may also prescribe and/or use hydroquinone which is still regarded as the most effective topical agent for reducing hyperpigmentation. Hydroquinone is available as a lotion, cream, or gel, and is applied directly to the discoloured patches of skin. It can, however, only be used for limited periods of time because, like other forms of chemical peel and laser treatment, it can irritate skin and actually cause post-inflammatory hyperpigmentation, especially in people with darker skin.