Snapshot A Middle Eastern 30-year-old woman comes to her obstetrician for recent darkening of her facial skin and neck. She is 34 weeks pregnant with her first baby. This has never happened to her before. Exacerbating factors include prolonged sun exposure, after which her face seems to darken more. She denies any pruritus or pain. She has no significant past medical history. Physical exam reveals symmetric macular eruption of hyperpigmentation on her face. Her laboratory values are all normal. Introduction Also known as chloasma Brown, hyperpigmentation of face and neck Epidemiology more commonly in women of darker skin tones often associated with high levels of estrogen pregnancy “mask of pregnancy” oral contraceptive pills Etiology unknown exacerbated by sun exposure Presentation Symmetric macular (flat) eruption of brown hyperpigmentation typically well-defined borders Common in the forehead, upper lip, chin, malar eminences, and neck Non-erythematous, non-inflammatory Evaluation Diagnosis based on clinical exam and history Differential Diagnosis Post-inflammatory hyperpigmentation Lentigines Treatment Topical hydroquinone (bleaching cream) with or without tretinoin cream Sun avoidance and sunscreen use Cessation of contraceptives Prognosis, Prevention, and Complications Usually fades over months after pregnancy or cessation of contraceptives