Melasma is a condition that causes hyperpigmented patches of skin, most typically occurring on the face in a symmetrical pattern and most commonly in women (however, it can appear anywhere on the body, and in men too).
Whilst it is ultimately not entirely clear what exactly causes melasma, the condition is associated with estrogen and progesterone sensitivity, which means factors such as pregnancy, hormone therapy and oral contraceptives can trigger the condition, as well as other lifestyle factors such as sun exposure, blue light and heat. Melasma is also thought to be triggered by stress and thyroid disease. Those with darker skin types are more at risk than those with fair skin. You can help prevent melasma by certain topical treatments, avoiding sun exposure, wearing a broad-spectrum SPF and avoiding intense heat. Melasma may disappear on its own, but there are also topical products and procedures which can help lighten affected areas
