In this video blog, Jenny Murase, MD, summarizes her lecture, Baby Bumps: Understanding the Dermatoses of Pregnancy , given on November 9, 2024, at the 5th Annual Elevate-Derm West Conference at the Westin Kierland Resort in Scottsdale, AZ.

In this video

Dr. Murase explains that antihistamines aren't off-limits in the third trimester, but they need to be used in a "measured" way. She cites a case of an infant who developed tonic-clonic seizures thought to reflect withdrawal after the mother took hydroxyzine 150 mg for itch, along with data linking antihistamine use within two weeks of delivery to a higher rate of retinopathy of prematurity (22% versus 11%) and the potential for increased uterine contractions at high doses — so the goal is to control itch while keeping levels lower.

Using a TH1/TH2 "yin and yang" analogy, she describes how estrogen shifts pregnant patients toward TH2 dominance, making atopic eruption of pregnancy the most common dermatosis of pregnancy — often the first manifestation of adult-onset atopic dermatitis. She contrasts these benign eruptions with intrahepatic cholestasis of pregnancy, a genetic condition with no primary skin lesions where bile acids cross the placenta and can cause placental insufficiency. Her rule of thumb: "when in doubt, order a bile acid and do a biopsy for direct immunofluorescence" to avoid missing cholestasis or pemphigoid gestationis.

  • Antihistamines can be used late in pregnancy but should be kept at measured, lower levels — high doses risk infant withdrawal, retinopathy of prematurity, and increased uterine contractions.
  • Atopic eruption of pregnancy is the most common dermatosis of pregnancy, driven by an estrogen-mediated shift toward TH2 (allergic) immunity, and may be the first sign of adult-onset atopic dermatitis.
  • Suspect intrahepatic cholestasis of pregnancy in a very itchy patient with no primary lesions — only secondary changes from scratching, and no baseline eczema or urticaria.
  • Order a simple bile acid blood test (plus liver function tests) when cholestasis is suspected, since bile acids cross the placenta and can cause placental insufficiency.
  • "When in doubt, order a bile acid and do a biopsy for direct immunofluorescence" to avoid missing cholestasis or pemphigoid gestationis.