Polymorphic eruption of pregnancy (PEP) is a skin condition that usually develops during the third trimester of pregnancy however, in rare cases, women can experience PEP as early as 20 weeks. PEPS effects mostly first-time mothers and women with multi-gestational pregnancies. In a study by researchers in Britain and Austria, data from 505 pregnant women was reviewed revealing 21.6% incidence of polymorphic eruption of pregnancy. PEP, or PUPPS (pruritic urticarial papules and plaques of pregnancy) as it is known in the United States, appears on the belly near the navel, often spreading to the legs, breasts, and arms. Polymorphic eruption of pregnancy usually clears after giving birth. However, some mothers continue to suffer from the rash up to six weeks after delivery with some complaining of recurrent itching during menstruation several years after giving birth. It is suspected that the persistence of the rash after delivery may be due to remnants of the placenta left in the womb. In approximately 7% of cases, women experience PEP during subsequent pregnancies.

Polymorphic Eruption of Pregnancy – Links to Fetal DNA

While the exact cause of Polymorphic eruption of pregnancy is unknown, its occurrence solely during pregnancy suggests an interaction between the mother and the fetus. A study published in The Lancet compared biopsies of women with PEP carrying male fetuses, female fetuses, and non-pregnant women found small amounts of fetal cells in PEP lesions. Using PCR primers to test for male DNA, six of the ten women with PEP were pregnant with male fetuses. Fetal cells can migrate from the uterus to the skin of the mother leading to dermatological disorders. These results suggest chimeric cells change the skin tissue.

Polymorphic Eruption of Pregnancy – General Tips

For women in their third trimester polymorphic eruption of pregnancy can lead to sleepless nights and desperation. There are many remedies however there are some general tips that all women should follow in order to be more comfortable. As difficult as it is, do not scratch. Scratching can worsen the inflammatory response and cause lesions in the skin making it susceptible to infection. Because the rash is feverish, try and stay cool. Heat and sunlight can make PEP more uncomfortable. Take warm to cool showers at least once a day. Women have also found milk baths and oatmeal soaks to be soothing to the skin as well. Using emollients such as creams or ointments are also soothing for the skin.  During the day a cold wet compress can provide spot relief. In general wear loose cotton clothing, or as some women advise, as little clothing as possible.