A 34-year-old woman, gravida 2 para 1, at 32 weeks gestation comes to the office for routine prenatal care. The patient reports no contractions, vaginal bleeding, or leakage of fluid. Fetal movement is normal. The patient reports a dark rash on her face that she first noticed 2 weeks ago. She has applied an over-the-counter moisturizer to the rash daily for the last week but has not noticed any improvement. The patient has no chronic medical conditions and no previous surgeries. She takes a daily prenatal vitamin and does not use tobacco, alcohol, or illicit drugs. The patient has no known drug allergies. She works as an accountant and enjoys gardening on the weekends. Blood pressure is 120/80 mm Hg and pulse is 65/min. The fetal heart rate is 140/min by Doppler ultrasound. Fundal height is 32 cm. Skin examination is shown in the image below. The remainder of the physical examination is unremarkable. Which of the following is the best next step in management of this patient?

Question

A 34-year-old woman, gravida 2 para 1, at 32 weeks gestation comes to the office for routine prenatal care.  The patient reports no contractions, vaginal bleeding, or leakage of fluid.  Fetal movement is normal.  The patient reports a dark rash on her face that she first noticed 2 weeks ago.  She has applied an over-the-counter moisturizer to the rash daily for the last week but has not noticed any improvement.  The patient has no chronic medical conditions and no previous surgeries.  She takes a daily prenatal vitamin and does not use tobacco, alcohol, or illicit drugs.  The patient has no known drug allergies.  She works as an accountant and enjoys gardening on the weekends.  Blood pressure is 120/80 mm Hg and pulse is 65/min.  The fetal heart rate is 140/min by Doppler ultrasound.  Fundal height is 32 cm.  Skin examination is shown in the image below.  The remainder of the physical examination is unremarkable.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

Explanation: This patient's rash is consistent with melasma, an acquired hyperpigmentation disorder that typically occurs on sun-exposed areas of the face. Melasma typically consists of irregularly shaped, hyperpigmented macules of varying color (light to dark brown or ash/blue). The rash occurs symmetrically in a malar (cheeks and nose), centrofacial (cheeks, forehead, upper lip, nose, and chin), or mandibular (jaw) distribution. Melasma is more common in women, especially during pregnancy, when elevated estrogen, progesterone, and melanocyte-stimulating hormone levels cause melanocyte stimulation, resulting in hyperpigmentation. Other risk factors include darker skin color, family history, thyroid dysfunction, medications (eg, antiepileptics, combination oral contraceptives), and use of cosmetics. Melasma is likely due to ultraviolet (UV) radiation exposure that triggers melanocyte proliferation in sun-exposed areas. Pregnancy-related melasma typically regresses spontaneously within the first year after delivery, although some areas do not completely resolve. The progression of melasma can be limited by minimizing sun exposure via protective clothing and application of a broad-spectrum sunscreen that blocks both UVA and UVB radiation. In addition to minimizing sun exposure, first-line treatment options include skin-lightening agents (eg, hydroquinone, azelaic acid) and topical retinoid creams. However, retinoids are contraindicated during pregnancy due to a high risk for spontaneous abortion and congenital defects (eg, craniofacial, cardiac, central nervous system) (Choice D). (Choice B) A morning serum cortisol concentration helps evaluate for adrenal insufficiency, which can present with generalized hyperpigmentation. Patients with adrenal insufficiency typically have concomitant fatigue, abdominal pain, and hypotension, which are not seen in this patient. (Choice C) Serum iron studies are indicated in the evaluation of hereditary hemochromatosis. However, hemochromatosis causes skin hyperpigmentation (eg, bronze discoloration) that is not confined to the face and presents with concomitant lethargy, arthralgias, liver function abnormalities, and diabetes mellitus, none of which are seen in this patient. (Choice E) Topical metronidazole is used for papulopustular rosacea, which can affect the cheeks, nose, and chin. However, this condition typically presents as persistent facial flushing, erythema, and inflammatory acneiform papules and pustules. papulopustular rosacea Educational objective: Melasma presents as irregularly shaped, hyperpigmented macules on the face. It occurs more commonly in women, especially during pregnancy. Management involves minimizing sun exposure and using a broad-spectrum sunscreen that blocks both UVA and UVB radiation. References: Evidence-based treatment for melasma: expert opinion and a review. (http://www.ncbi.nlm.nih.gov/pubmed/25269451)

A 34-Year-Old Woman, Gravida 2 Para 1, at 32 Weeks