Hyperpigmentation is the term used to cover a number of conditions where one area of skin becomes darker than the surrounding skin of the same area. This term covers a number of more specific conditions such as liver spots, freckles and melasma.
Melasma is one form of hyperpigmentation, also called ‘chloasma’ and ‘pregnancy mask’. It is a common skin condition in adults in which brown or greyish patches of pigmentation (colour) develop, usually on the face. The name comes from melas, the Greek word for black, or cholas, from the word green-ish. It is more common in women, particularly during pregnancy (when up to 50% of women may be affected). Sometimes men may also be affected. Melasma is more common in people of colour and those who tan very quickly but can occur in anyone.
Melasma usually becomes more noticeable in the summer and improves during the winter months. It is not an infection; therefore, it is not contagious, and it is not due to an allergy. It is not cancerous and will not develop into skin cancer.
The exact cause is not known, but it is thought to be because of pigment-producing cells in the skin (melanocytes) producing too much pigment (melanin). Several factors can contribute to developing melasma, including pregnancy and using hormonal drugs such as birth control pills and hormone replacement. Rarely, other medical problems that affect hormones (such as thyroid problems) may cause melasma, as well as some other medications, such as anti-epileptics.
Exposure to ultraviolet (UV) light from the sun and the use of sunbeds or phototherapy can trigger melasma or make it worse.
Melasma treatments fall into the following categories and can be used together:
Skin affected by melasma darkens more than the surrounding skin when exposed to light, so sun-avoidance and sun-protection are important (see the ‘top sun safety tips’ below for more information).
One of the most important things you can do to prevent melasma worsening is protecting yourself from UV radiation. This means avoiding the sun, wearing a wide-brimmed hat when you are outside and wearing broad-spectrum sun cream (SPF 30 or above, with a high UVA rating). The higher the SPF the more effective it will be. Avoid using sun-tanning beds. Protecting your skin from the sun will also help the below treatments be more effective.
Hydroquinone is a medicine that prevents pigment cells in the skin from producing melanin and is commonly used to treat melasma. Hydroquinone creams may cause skin irritation, and they should only be used for a few weeks at a time to prevent over-lightening of the skin. Hydroquinone can only be prescribed by doctors and may occasionally cause the skin to become darker. Retinoid creams, usually used to treat acne, and some types of acid cream (such as azelaic acid, ascorbic acid and kojic acid) can help improve the appearance of melasma but can also cause skin irritation. Steroid creams can also be useful and are often mixed with the above chemicals to help prevent skin irritation.
Some skin-lightening creams contain a combination of two or three ingredients to make them more effective. Skin lightening creams must only be used when prescribed, and under medical supervision to reduce the risk of side effects.
This information is courtesy of the British Association of Dermatologists Rosacea leaflet.