Polymorphic Eruption of Pregnancy (Pruritic Urticarial Papules and Plaques of Pregnancy; PUPPP) By Antonette T Dulay, MD, Main Line Health System Reviewed / Revised Oct 2022 | Modified Nov 2022 View Patient Education Symptoms and Signs Diagnosis Treatment Key Points Polymorphic eruption of pregnancy is benign pruritic skin eruptions of unknown cause that develop during pregnancy.