Polymorphic Eruption of Pregnancy Clinical Presentation

Updated: Feb 21, 2020
  • Author: Joseph C Pierson, MD; Chief Editor: William D James, MD  more...
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Presentation

History

Polymorphic eruption of pregnancy (PEP) typically begins with intensely pruritic papules arising within striae distensae late in the third trimester of a first pregnancy. Of all cases, 73% are seen in primigravidae pregnancies. [4] Additionally, 11.7 % of affected females are multiple-gestation pregnancies. [7]

As many as 15% of PEP cases arise in the immediate postpartum period, [4] and in one case report 2 weeks postpartum. [14] In a few days, the eruption spreads to the buttocks and proximal thighs and may generalize. Patients present for a diagnosis of their unusual skin eruption and seek relief from the intense itching.

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Physical Examination

In classic polymorphic eruption of pregnancy (PEP), papules occur within prominent striae distensae, as shown in the images below.

Papules within prominent striae distensae. Courtes Papules within prominent striae distensae. Courtesy of Jeffrey P. Callen, MD of Louisville, Kentucky.
Papules within prominent striae distensae. Courtes Papules within prominent striae distensae. Courtesy of Jeffrey P. Callen, MD of Louisville, Kentucky.

Similar lesions are often found on the buttocks and proximal thighs and may generalize elsewhere over the trunk and extremities, although the periumbilical area is characteristically spared. Small vesicles often are noted, but larger bullae, though documented in one case, typically do not occur and would suggest the possibility of pemphigoid gestationis. [15, 16] Less commonly, target lesions [17]  and annular and polycyclic wheals may be present. PEP usually does not affect the face, palms, or soles.

Although the eruption is intensely pruritic, excoriations rarely are found. One report described a case of PEP that progressed to involve the neck, arms, and legs in a photosensitive distribution as the initial abdominal involvement settled. [18]

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