Hyperpigmentation: what it is, causes, treatment and sun protection

Treatment depends on the cause. The PCDS says that for post-inflammatory hyperpigmentation, treatment is of the primary disorder: the skin develops less pigmentation if the skin condition is treated promptly and effectively.

For melasma, the BAD says there is no cure at present, but several treatment options may improve appearance, and they can be used together. Even if treated, melasma often returns after stopping.

The BAD says skin affected by melasma darkens more than surrounding skin when exposed to light. Its advice is to avoid the sun, wear a wide-brimmed hat, and use broad-spectrum sun cream (SPF 30 or above, with a high UVA rating). Sun cream containing iron oxides can provide added protection against visible light.

It also advises using shade between 11am and 3pm, wearing UV-protective sunglasses, applying sunscreen 15 to 30 minutes before going out and reapplying every two hours, and avoiding sunbeds.

The BAD says to use gentle, fragrance-free skin care and to avoid irritating products.

Hyperpigmentation is an increase in skin colour in patches caused by extra melanin. The PCDS says facial hyperpigmentation is common and can cause significant emotional impact.

The BAD says melasma is thought to be due to pigment-producing cells (melanocytes) producing too much pigment. It says the affected skin is not itchy or painful and the patches are flat, not raised, appearing darker on the cheeks, forehead, upper lip, nose and chin, and sometimes forearms and neck.

The PCDS sorts causes into groups so that serious causes are not missed:

The BAD says the exact cause of melasma is not known, but pregnancy and hormonal drugs such as birth control pills and hormone replacement can contribute. Rarely, thyroid problems or some anti-epileptic medicines may cause it. UV light, sunbeds and phototherapy can trigger or worsen it.

It says melasma is more common in people of colour and those who tan quickly, and usually becomes more noticeable in the summer and improves during the winter.

The BAD says melasma is usually recognised from its appearance. Occasionally a dermatologist may take a small skin sample (biopsy) to exclude other conditions. The PCDS says a Wood's light may help show whether pigment is in the epidermis, which is more likely to respond to treatment.

The BAD says melasma is also called "pregnancy mask" and is more common in women, particularly during pregnancy, when up to 50% of women may be affected.

It says if melasma occurs during pregnancy it may go away a few months after delivery, and treatment may not be necessary, although it may come back during another pregnancy. It advises that hydroquinone and retinoid creams should be avoided in pregnancy because they could harm the baby in the womb.

The BAD says skin-lightening creams must only be used when prescribed and under medical supervision to reduce the risk of side effects, and that hydroquinone can only be prescribed by doctors and may occasionally cause the skin to become darker.

The PCDS lists medicines that can cause hyperpigmentation, so tell your GP about every medicine you take. Do not stop a prescribed medicine without speaking to the prescriber.

The BAD says to tell your doctor about any changes to a mole or patch of skin. See a GP for a patch that is new, changing in size, shape or colour, itchy, bleeding or does not look like the rest of your skin.

Because the PCDS lists Addison's disease and haemochromatosis among rare but important causes, also mention fatigue, weight loss, dizziness on standing, or darkening of the gums, palmar creases or scars.

For sudden severe illness, such as collapse or repeated vomiting with severe tiredness, call 999 or NHS 111.

On the NHS, a GP can examine the skin, review medicines and arrange tests. The BAD says chemical peels, microneedling and laser are usually not available as NHS procedures, so these tend to be arranged privately. Choose reputable, qualified providers with experience in your skin type, and ask about test patches and risks of worsening pigmentation.