Polymorphic eruption of pregnancy
Polymorphic eruption of pregnancy is an itchy, bumpy rash that starts in the stretch marks of the abdomen in the last 3 months of pregnancy then clears with delivery.
It is also called PUPPP or Pruritic Urticarial Papules and Plaques of Pregnancy.
What causes polymorphic eruption of pregnancy?
Polymorphic eruption of pregnancy is thought to be related to stretching of the skin on the abdomen. Somehow the rash develops as a sort of "allergy" to the stretch marks and spreads elsewhere on the body. Supporting the stretch mark theory are the following observations:
- Most cases begin in the last 3 months, especially the last 5 weeks, when the stretching is greatest. It is rare for polymorphic eruption of pregnancy to begin after delivery.
- Polymorphic eruption of pregnancy is most common in a first pregnancy, when the abdomen is tightest.
- The rash usually starts around the umbilicus where stretching of the abdomen is greatest.
- On average, patients with polymorphic eruption of pregnancy have greater weight gain, babies that are heavier than normal and an increased chance of having twins.
Another theory considers low level traffic of fetal cells within the mother's circulation, which appears increased in women with PUPPP and may persist for some time after the baby has been born.
What are the features of polymorphic eruption of pregnancy?
Small, pink, raised spots (papules) appear in the stretch marks around the umbilicus. There is often a pale halo around the papules. These papules coalesce to form large red, raised (urticarial) patches (plaques) which spread to involve the buttocks and thighs, and sometimes the arms and legs. Lesions on or above the breasts are rare.
PUPPP is very itchy (pruritic) and patients find it difficult to sleep at night.
Does polymorphic eruption of pregnancy affect the baby?
Rarely, the baby can be born with a mild polymorphic eruption of pregnancy rash but this soon fades. polymorphic eruption of pregnancy does not cause any other problem with the baby.
How long does polymorphic eruption of pregnancy last?
Polymorphic eruption of pregnancy continues until delivery then usually resolves within a few weeks. Rarely, it may persist for longer. In some cases, this relates to retained placental products.
Treatment of polymorphic eruption of pregnancy
There is no curative treatment for polymorphic eruption of pregnancy (apart from delivery!). Symptoms can be controlled using:
- Emollients (moisturisers) applied liberally and frequently as required.
- Topical steroids applied thinly twice daily to the red itchy patches.
- Antihistamines - conventional antihistamine tablets appear safe in late pregnancy (though they may make the baby drowsy on delivery).
Discuss your treatment with your doctor, or ask to be referred to a dermatologist.
Can polymorphic eruption of pregnancy recur with future pregnancies?
It is very uncommon for polymorphic eruption of pregnancy to recur. If it occurs, it is likely to be milder.