A 25-year-old pregnant woman in her second trimester develops intensely pruritic urticarial papules and plaques in the periumbilical area, sparing the umbilicus, and subsequently vesicles on the abdomen. DIF of perilesional skin shows linear C3 ± IgG at the dermo-epidermal junction. What is the diagnosis and the fetal risk?
- A Pemphigoid gestationis; risk of small-for-gestational-age infant and premature birth ✓
- B Pruritic urticarial papules and plaques of pregnancy (PUPPP); no significant fetal risk
- C Intrahepatic cholestasis of pregnancy; risk of stillbirth
- D Impetigo herpetiformis; risk of placental insufficiency
Explanation
Pemphigoid gestationis (herpes gestationis) is an autoimmune sub-epidermal blistering disorder of pregnancy driven by IgG1 autoantibodies against BP180 (NC16A domain). It characteristically begins periumbilically and later generalises. The unique DIF finding is linear C3 deposition (often without IgG) at the DEJ due to complement activation. Maternal antibodies cross the placenta and cause neonatal pemphigoid gestationis (transient blisters in the neonate) and are associated with preterm delivery and small-for-gestational-age infants. PUPPP (polymorphic eruption of pregnancy) lacks DIF findings and carries no fetal risk.
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.