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A young Hispanic woman delivers a healthy baby boy. On the first postpartum day, she is sitting in the rocking chair after breastfeeding her son. Her doctor notes that she has melasma and asks her about it. She states that the hyperpigmented areas on her face have become darker during this pregnancy (Figure 205-1). She noted the dark spots started with her first pregnancy but they are worse this time. On physical examination, hyperpigmented patches are noted on the cheeks and upper lip (Figure 205-2). Although the patient hopes the pigment will fade, she does not want to treat the melasma at this time.
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Melasma is an acquired hyperpigmentary disorder characterized by symmetric light- to dark-brown macules and patches occurring in the sun-exposed areas of the face and neck. It is most commonly caused by pregnancy or the use of sex steroid hormones, such as oral contraceptive pills.
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Chloasma, chloasma gravidarum, mask of pregnancy.
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It is a relatively common disorder that affects sun-exposed areas of skin, most commonly the face. The prevalence within populations varies according to ethnic composition, dermal phototypes, and intensity of sun exposure. It is believed to affect 5% to 50% of women.1
It affects predominantly women (Figures 205-1, 205-2, 205-3), with men accounting for only 10% of all cases (Figure 205-4.) It is particularly prevalent in women of Hispanic, East Asian, Indian, Pakistani, Middle Eastern, and Mediterranean-African origin (skin types IV to VI) and who live in areas of intense UV radiation exposure.1
Melasma caused by pregnancy usually regresses within a year, but areas of hyperpigmentation never completely resolve in about 30% of patients.1,2 There is a 6% rate of spontaneous remission. Melasma may increase, becoming more obvious with each subsequent pregnancy.
There appears to be a genetic predisposition for the condition, because over 40% of patients reported having relatives affected with the disease.1
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