Polymorphic Eruption of Pregnancy (PEP)

The aims of this leaflet

This leaflet is designed to tell you more about Polymorphic eruption of pregnancy (PEP). It tells you what the condition is, what causes it, what can be done about it and where to find out more about it.

What is Polymorphic eruption of pregnancy?

Polymorphic eruption of pregnancy is a relatively common skin disorder that occurs in pregnant women. It usually starts in women during their first pregnancy and rarely recurs in later pregnancies. 
It is characterised by an itchy rash that commonly begins on the abdomen, particularly within stretch marks (striae). It most usually develops during late pregnancy (third trimester) but can also start immediately after the baby is born. It was previously known as PUPPP (pruritic urticarial papules and plaques of pregnancy) but this name is no longer used.  

What causes Polymorphic eruption of pregnancy?

The cause of PEP is unknown although there have been many theories about it. Previous studies have suggested a link with increased weight gain during pregnancy, large babies, sex hormones and the sex of the baby but none of these have been proven. It more commonly occurs with multiple pregnancy (twins or triplets). There are no specific tests for PEP and it can be confused with other skin conditions presenting in pregnancy.  

Does Polymorphic eruption of pregnancy run in families?



Itching is common and often starts on the abdomen often sparing the umbilicus (belly button) during late pregnancy (3rd trimester). If stretch marks (striae) are present the itching may start within them. Itching may then be followed by a rash with wheals (like hives or nettle rash), small raised lumps in the skin (papules) and large red inflamed areas of skin (plaques). It commonly spreads on the trunk, lower abdomen, under the breasts and limbs. The face, scalp mouth and genital area are hardly ever affected.  Small blisters are sometimes present and if these are scratched then straw-coloured fluid may leak out and cause crusts to form.   

How will Polymorphic eruption of pregnancy be diagnosed?

Diagnosis is usually based on the typical appearance and distribution of the rash, but may be confirmed by taking a sample of skin (skin biopsy). Usually the appearance and behaviour of the rash is very typical, but in some cases the rash can look like other skin diseases such as eczema or a drug eruption. In some cases a special test is done on blood and a skin biopsy to rule out a more serious skin condition.  

Can Polymorphic eruption of pregnancy be cured?

In most cases this condition and the symptoms will disappear towards the end of pregnancy or immediately following delivery. It can be suppressed with treatment  

How can Polymorphic eruption of pregnancy be treated?

The primary aim of treatment is to relieve itching and to reduce inflammation and redness in the skin. It is also important during pregnancy to use treatments that are entirely safe for both mother and baby.
Emollient (moisturising) creams or ointments can also be applied to reduce itching and soothe sore areas. Bath emollients and soap substitutes are also helpful in many cases.
Steroid creams or the greasier steroid ointments are often necessary to relieve symptoms. The steroid cream or ointment should only be applied to affected areas of skin and a mild (for example hydrocortisone) or moderate steroid cream should be used. The amount should be as small as possible, and ideally only 1-2 small (15-30gm) tubes should be used for a few days and intermittently. However, if the condition is severe then application of a stronger steroid cream or ointment to the skin in larger quantities is still better than steroids given by mouth. Treatment with high doses of steroid tablets may be required for severe disease. Alternatively early delivery can be considered. The dose of steroid tablets can usually be reduced quickly (within 3-5 days) after delivery once the rash starts to disappear.
Antihistamines may be helpful to treat the itch. The following are considered safe in pregnancy:
sedating (drowsy making): Clemastine, Dimethindene, Chlorpheniramine 
Non-sedating: Loratadine, Cetirizine.

Will Polymorphic eruption of pregnancy come back?

It is unusual for PEP to recur in further pregnancies; if it does it is usually milder. 

Will the baby be affected?

It has been suggested that PEP occurs more commonly in women who gain more weight late in pregnancy, have larger babies and in women with multiple pregnancy (twins or triplets).  

Is normal delivery possible?

Yes. Caesarean section is not recommended for this condition.  

Are the treatments safe for the baby and mother?

Mild to moderate strength steroid creams or ointments appear to be safe during pregnancy but stronger steroid creams and ointments may cause problems with the growth of the unborn baby, so that they may be born small if the mother is using large amounts (more than 50 gm, 1/2 large tube per month or over 200-300gm, 2-3- large tubes, in the whole pregnancy) of steroid creams or ointments.
When steroid tablets are taken there is an increased risk in the mother of developing diabetes (raised sugar levels) and hypertension (raised blood pressure). Careful observation of blood pressure and urine checks are therefore essential at antenatal clinic, while ultrasound scans can look for any changes in the baby’s growth.  

Can women with Polymorphic eruption of pregnancy still breastfeed?

Yes. Breastfeeding does not appear to affect PEP. Even while taking oral steroid tablets women should still be encouraged to breastfeed as only negligible amounts of steroid get into breast milk.   

Is any special monitoring required?

Yes, regular review at an antenatal clinic is important to monitor foetal size. Blood tests, urine tests, blood pressure checks with ultrasound scans are all important to monitor the mother and baby’s wellbeing.  

Where can I get more information about Polymorphic eruption of pregnancy?

Web links to detailed leaflets

This leaflet has been prepared by the EADV task force “skin disease in pregnancy”, it does not necessarily reflect the official opinion of the EADV.
Updated July 13