History and exam

Key diagnostic factors

common

centrofacial, malar, or mandibular distribution of muddy brown to grey hyperpigmentation

Muddy brown to grey hyperpigmentation in a typical distribution (i.e., centrofacial, malar, mandibular) suggests a diagnosis of melasma. The central facial pattern is the most common pattern seen; however, hyperpigmentation can sometimes affect different areas, such as the forearms and neck.[3][Figure caption and citation for the preceding image starts]: MelasmaFrom the collection of Dr Laura Ferris [Citation ends].com.bmj.content.model.Caption@72ae1137

Risk factors

strong

female sex

Women account for approximately 90% of all melasma patients.[7][8][9] This is likely to be due to the influence of hormones on melanogenesis. The age of onset is between 20 and 29 years in 50% of patients.[10]

Fitzpatrick III to VI skin types

Hispanic and Asian women are affected by melasma more frequently than women with lighter skin types.[6] Women with black hair are more frequently affected and are at increased risk of having severe or very severe melasma according to the Melasma Area and Severity Index (MASI) score.[10]

ultraviolet radiation

Melasma is exacerbated following sun exposure and fades with sun protection.[3]

oral contraceptive pill

Any oestrogen-containing drug may cause melasma, including transdermal hormones and hormone replacement therapy (HRT). Melasma is seen more frequently in women who use oral contraceptives.[16]

pregnancy

Up to 60% of pregnant women will develop melasma, with it being more common in the third trimester.[16] This phenomenon can be explained by the association between increased levels of melanin-stimulating hormone (MSH), post-inflammatory phenomenon, and ultraviolet light exposure in pregnant women.[10]

family history of melasma

Up to 50% of melasma patients have a family history of the disease.[11][17][18] One study showed that in 97% of these patients, it is a first-degree relative who is affected.[10]

weak

photosensitising drugs

Some photosensitising drugs, including furosemide, ACE-inhibitors, beta-blockers, hydrochlorothiazide, and anti-seizure medications, may lead to the development of melasma.[1] The incidence of melasma seems to be increased in patients taking anti-seizure medications.[17]

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