Question

A 28-year-old G1P0 woman at 38 weeks’ gestation presents with a 1-week history of intensely pruritic rash on the abdomen. She reports the rash is limited to the abdomen, denies mucosal involvement, fevers, or prior similar episodes. On examination, there are erythematous urticarial papules coalescing into plaques within the abdominal striae. The periumbilical region is spared.

Which of the following fetal risks is most strongly associated with this condition?

1. Increased risk of stillbirth
2. Preterm delivery and small-for-gestational-age infant
3. Neonatal blistering
4.No increased fetal risk
5. Neonatal hypothyroidism

Correct Answer

Correct Answer: D. No increased fetal risk

Explanation

This patient’s presentation is most consistent with Polymorphic Eruption of Pregnancy (PEP) or Pruritic Urticarial Papules and Plaques of Pregnancy (PUPPP), a benign dermatosis that typically occurs in the third trimester, most often in primiparous women. The eruption characteristically begins within the abdominal striae and spares the umbilicus, presenting as intensely pruritic urticarial papules and plaques. As the name suggests, there can be variable clinical presentations beyond urticaria, including vesicles, diffuse erythema, targetoid lesions, or eczematous plaques. Importantly, polymorphic eruption of pregnancy is not associated with placental dysfunction, autoantibody formation, or systemic maternal disease. As a result, it does not increase the risk of stillbirth, preterm delivery, fetal growth restriction, or neonatal skin disease. PEP usually does not reoccur with future pregnancies. Management is symptomatic (topical steroids and/or antihistamines may be used), and no change in obstetric management is required.

Choice A, increased risk of stillbirth, is most strongly associated with intrahepatic cholestasis of pregnancy. In this condition, patients experience intense pruritus—often involving the palms and soles—without primary inflammatory skin lesions. Elevated serum bile acids are linked to fetal arrhythmias and stillbirth, which is why early delivery is often considered. Management involves reducing serum bile acids using ursodeoxycholic acid. The presence of primary urticarial papules and plaques in this patient makes cholestasis unlikely.

Choice B, preterm delivery and small-for-gestational-age infant, is associated with pemphigoid gestationis, an autoimmune subepidermal blistering disease caused by autoantibodies targeting BP180 (type XVII collagen). Pemphigoid gestationis typically begins in the periumbilical region with urticarial plaques and may progress to vesicles and tense bullae. It carries risks of placental involvement, preterm birth, and fetal growth restriction. Sparing of the periumbilical area and lack of vesicles/bullae argues against this diagnosis.

Choice C, neonatal blistering, can also occur in pemphigoid gestationis due to transplacental transfer of pathogenic IgG autoantibodies. A small percentage of neonates develop transient blisters after birth. Because polymorphic eruption of pregnancy is not antibody-mediated, this complication does not occur. Choice E, neonatal hypothyroidism, is not associated with any of the common pregnancy-specific dermatoses and serves as a distractor.

References

References 1. Ambros-Rudolph CM. Pregnancy dermatoses. In: Bolognia J, Schaffer JV, Cerroni L, eds. Dermatology. 5th ed. Elsevier; 2025:480-490.