Vesiculobullous disorders: neonatal pemphigus: practice question

A Dermatology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Dermatology · Vesiculobullous disorders: neonatal pemphigus

Sample item

A newborn of a mother with active pemphigus vulgaris has a few flaccid blisters and erosions that heal without treatment over a few weeks. What is the mechanism?

ANeonatal infection with herpes simplex virusBTransplacental passage of maternal IgG autoantibodiesCInherited defect in keratin 14DFetal production of anti-desmoglein IgM

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Transplacental passage of maternal IgG autoantibodies

Maternal IgG against desmogleins crosses the placenta and transiently causes blisters in the newborn. Disease resolves as the passive antibodies are catabolised over weeks, so no immunosuppression is needed, only skin care.

Option by option

A. Neonatal infection with herpes simplex virus
Neonatal HSV causes grouped vesicles with systemic illness and requires urgent acyclovir.
B. Transplacental passage of maternal IgG autoantibodies (correct)
Correct. Passive transfer of maternal IgG explains the transient self-limiting disease.
C. Inherited defect in keratin 14
A keratin 14 defect causes epidermolysis bullosa simplex, which persists and is not transient.
D. Fetal production of anti-desmoglein IgM
Pathogenic antibodies in pemphigus are IgG, and IgM is too large to cross the placenta.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Dermatology question

What is the answer to this Dermatology question?

The best answer is B, Transplacental passage of maternal IgG autoantibodies. Maternal IgG against desmogleins crosses the placenta and transiently causes blisters in the newborn.

Why is "Neonatal infection with herpes simplex virus" not the answer?

Neonatal HSV causes grouped vesicles with systemic illness and requires urgent acyclovir.

Why is "Inherited defect in keratin 14" not the answer?

A keratin 14 defect causes epidermolysis bullosa simplex, which persists and is not transient.

Why is "Fetal production of anti-desmoglein IgM" not the answer?

Pathogenic antibodies in pemphigus are IgG, and IgM is too large to cross the placenta.

What concept does this question test?

It tests Vesiculobullous disorders: neonatal pemphigus in Dermatology. Disease resolves as the passive antibodies are catabolised over weeks, so no immunosuppression is needed, only skin care.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Vesiculobullous disorders: neonatal pemphigus?

Learn each condition by its primary lesion, site and signature sign. Then use the flashcards and the other Dermatology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.