Polymorphic eruption of pregnancy is benign pruritic skin eruptions of unknown cause that develop during pregnancy.
Most cases of polymorphic eruption of pregnancy occur during a first pregnancy. Overall incidence is estimated to be 1/200 pregnancies (1); however, with multiple gestation, risk is 8 to 12 times higher.
Reference
1. Himeles JR, Pomeranz MK. Recognizing, Diagnosing, and Managing Pregnancy Dermatoses. Obstet Gynecol. 2022;140(4):679-695. doi:10.1097/AOG.0000000000004938
Symptoms and Signs of Polymorphic Eruption of Pregnancy
Lesions are intensely itchy, erythematous, solid, superficial, and elevated; some are surrounded by blanching, and some have minute vesicles in the center. Itching keeps most patients awake, but excoriation is uncommon. Lesions begin on the abdomen, frequently on striae atrophicae (stretch marks), and spread to the thighs, buttocks, and occasionally the arms. The palms, soles, and face are usually spared. Most patients have hundreds of lesions.
Lesions develop during the third trimester, most often in the last 2 to 3 weeks and occasionally in the last few days or postpartum. They usually resolve within 15 days after delivery but can take longer. They may recur in up to 5% of subsequent pregnancies.
Diagnosis of Polymorphic Eruption of Pregnancy
Skin examination
Polymorphic eruption of pregnancy is diagnosed by examining the skin. Differentiation from other pruritic eruptions may be difficult. Early lesions of polymorphic eruption of pregnancy usually start in striae on the abdomen; in pemphigoid gestationis, early lesions are usually periumbilical.
Treatment of Polymorphic Eruption of Pregnancy
Corticosteroids
Nonsedating oral antihistamines
Supportive care
Nonsedating oral antihistamines can also be used to relieve pruritus.
Key Points
Polymorphic eruption of pregnancy consists of intensely itchy skin lesions that usually develop during the last 2 to 3 weeks of pregnancy and resolve within 15 days after delivery.
Differentiating these lesions from others pruritic eruptions may be difficult.
Treat with topical corticosteroids for mild symptoms and oral corticosteroids for more severe symptoms.
