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PEP — SCE Dermatology MCQ

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ModeratePaediatric DermatologyPEPSCE Dermatology

A 25-year-old woman develops widespread urticarial plaques with central vesiculation during her third trimester of pregnancy. Onset is within striae on the abdomen. DIF is negative. She is primigravida with a twin pregnancy. What is the most likely diagnosis?

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Reveal the answer and explanation

Correct answer: A — Polymorphic eruption of pregnancy beginning within abdominal striae

Explanation lettering: D = shown as A · E = shown as B · A = shown as C · C = shown as D · B = shown as E

D is correct. PEP usually begins in abdominal striae late in a first pregnancy, is more frequent with multiple pregnancy, tends to spare the umbilicus and has negative direct immunofluorescence. A causes excoriated papules or nodules, often on extensor surfaces, rather than a striae-centred urticarial eruption. B commonly begins earlier and is associated with an atopic phenotype. C often begins around the umbilicus and shows linear C3 at the basement membrane zone. E causes pruritus without a primary inflammatory eruption and is investigated with liver tests and bile acids. PEP is treated symptomatically and does not carry the fetal risks of pemphigoid gestationis or cholestasis.

Reference: BAD polymorphic eruption of pregnancy information: https://www.bad.org.uk/pils/polymorphic-eruption-of-pregnancy