Snapshot A 30-year-old G1P0 woman presents to her obstetrician with a new itchy rash. She is 36 weeks pregnant. The rash has been present for a week now with intense pruritus. She denies any other symptoms, including shortness of breath, swelling of the eyes, or fever. She denies any exposure to new medications or allergens. On physical exam, there are multiple erythematous urticarial plaques within the stretch marks on her abdomen. The umbilicus is spared. Introduction Pruritic urticarial papules and plaques of pregnancy (PUPPP) or polymorphic eruption of pregnancy (PEP) A self-limited pruritic inflammatory disorder of the skin occurring in the last trimester of pregnancy or immediately postpartum Epidemiology Common in primiparous women Common in women with multiple gestation pregnancies ETIOLOGY Pathogenesis login to view 2 more bullets Presentation Symptoms login to view 6 more bullets Evaluation Diagnosis is usually based on history and physical exam Skin biopsy only if diagnostic uncertainty login to view 1 more bullet No lab abnormalities Differential Diagnosis Pemphigoid gestationis Erythema multiforme Other drug reaction rash Treatment Initial therapy login to view 1 more bullet If refractory login to view 1 more bullet Anti-histamines for pruritus Prognosis Resolves typically in 4-6 weeks or within 2 weeks postpartum No risk of fetal or maternal morbidity