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Specific dermatoses of pregnancy
The four skin diseases specific to pregnancy differ on one question — do they endanger the fetus: intrahepatic cholestasis of pregnancy and pemphigoid gestationis do, PEP (PUPPP) and atopic eruption of pregnancy do not.
Why it matters in the exam
Exam stems show a woman in the third trimester with itch. If there is itch of the palms and soles without a primary rash — think cholestasis and check bile acids. If there are papules within striae that spare the umbilicus in a first pregnancy — PEP. If blisters start around the umbilicus — pemphigoid gestationis. The question tests the distinction, the decisive test and the fetal risk, and also treatment with ursodeoxycholic acid and timing of delivery. Remember that itch in pregnancy is common, that most cases are benign, and that the key skill is to identify the few conditions that need blood tests and close fetal surveillance, and to explain to the woman when she can relax and when she must return at once. In all cases the dermatologist and the obstetric team should coordinate.
Key points
- There are four pregnancy-specific dermatoses: cholestasis, pemphigoid gestationis, PEP and AEP.
- Cholestasis presents with itch of the palms and soles without a rash and is diagnosed by raised bile acids; it raises the risk of preterm birth and stillbirth.
- Pemphigoid gestationis starts around the umbilicus, is diagnosed by DIF with linear C3 and may cause a small baby and preterm birth.
- PEP appears in the striae in a first pregnancy, spares the umbilicus and does not endanger the fetus.
- AEP is an early eczematous rash in an atopic background, benign for the fetus and treated with emollients and topical steroids.
Summary table
| Disease | Feature | Decisive test | Fetal risk and treatment |
|---|---|---|---|
| Intrahepatic cholestasis of pregnancy | Itch of palms and soles, at night, third trimester, no primary rash | Raised serum bile acids (10 µmol/L or more) | Preterm birth, stillbirth with bile acids above 100; ursodeoxycholic acid and delivery timing |
| Pemphigoid gestationis | Periumbilical papules and wheals, then tense blisters, second or third trimester | DIF: linear C3 along the basement membrane; anti-BP180 antibodies | Small-for-gestational-age baby and preterm birth; steroids; may recur in later pregnancies |
| PEP (PUPPP) | Itchy papules and plaques within striae, sparing the umbilicus, first pregnancy, twins | Clinical diagnosis | No fetal risk; topical steroids and antihistamines |
| AEP — atopic eruption of pregnancy | Eczema or itchy papules, early in pregnancy, atopic background | Clinical diagnosis; IgE sometimes raised | No fetal risk; emollients and topical steroids |
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Sources
- Royal College of Obstetricians and Gynaecologists Green-top Guideline Intrahepatic Cholestasis of Pregnancy, 2022 — Diagnosis and management
- EADV Task Force on Dermatoses in Pregnancy position statement, 2022 — Specific dermatoses of pregnancy
- British Association of Dermatologists guideline for pemphigoid gestationis, 2023 — Management
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.