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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 197-1). 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 197-2). 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 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, mask of pregnancy.
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- It is a relatively common disorder that affects sun-exposed areas of skin, most commonly the face. It is believed to affect up to 75% of pregnant women.1
- It affects predominantly women (Figures 197-1, 197-2, and 197-3), with men accounting for only 10% of all cases. It is particularly prevalent in women of Hispanic, East Asian, and Southeast Asian 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 may never completely resolve.2 It may increase with each subsequent pregnancy becoming more obvious.
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The major etiologic factors include genetic influences, exposure to UV radiation, and sex hormones.
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- The precise cause of melasma has not been determined. Multiple factors have been implicated, including pregnancy, oral contraceptives, genetics, sun exposure, cosmetic use, thyroid dysfunction, and antiepileptic medications.3,4
- Women with melasma not related to pregnancy or oral contraceptive use may have hormonal alterations that are ...