It’s called polymorphic eruption of pregnancy (PEP) and has also been called pruritic urticarial papules and plaques of pregnancy (PUPP), but either way it is an itchy rash that develops late in pregnancy. It is most common with a first pregnancy. PEP is not dangerous to you or your baby, but it is very itchy and it can keep you awake at night, the last thing you need late in your third trimester. [1,2]
Signs and Symptoms of PEP
The PEP rash starts in the last three months of pregnancy. It begins as tiny pink dots in the stretch marks of your belly, especially right around your belly button. The pink dots – called papules – come together to form larger, red, raised patches – called plaques – that become very itchy. [1,2]
There may also be tiny, fluid-filled blisters, called vesicles. The rash may spread to your thighs and buttocks. The good news is that PEP only lasts about 4 to 6 weeks. And more good news, it is unlikely to occur again during a future pregnancy. [1,2]
What Causes PEP?
The most likely cause is stretching of the skin. This may cause your body to treat the stetching as an injury and send in immune cells that cause inflammation, hence the redness and itching. Another theory is that DNA from your baby circulating in your skin cells causes the reaction. [1,2]
Who Gets PEP?
About 1 in 160 pregnant women get PEP. You could be at higher risk if: [1,2]
- This is your first pregnancy
- You are having twins or multiples
- You have white skin rather than dark skin
- You are having a boy (PEP is twice as common with boy babies).
- You gain a lot of weight during pregnancy
What Can You Do About PEP?
Start by letting your doctor know about the rash. Although PEP is not harmful to you or your baby, there are some other pregnancy skin rashes that can look like PEP but need different types of treatment. In most cases, your doctor will be able to diagnose PEP just by examining you. [1,2]
There is no treatment to make PEP go away, but you can treat the symptoms and be more comfortable until PEP goes away on its own. Here are the options: [1,2]
- Use a moisturizer frequently. Ask your doctor to recommend a moisturizer for you.
- Try cool baths and cool compresses to relieve itching.
- Wear light cotton clothing.
- The most common treatment for PEP is a topical steroid cream. Your doctor can write a prescription if you need it.
- If PEP is keeping you up at night, your doctor may recommend an antihistamine. This will relieve itching and make you drowsy. Antihistamines are considered safe in the third trimester.
Stretch marks, a big swollen belly, fatigue, and then PEP. The third trimester can be tough enough without an itchy rash. Odds are in your favor that you won’t have to deal with it, but if you do, treatment can help, and it only lasts for a short while. Don’t panic, just work with your doctor to stop the itching. In a few months it will be a distant memory and you probably won’t have to deal with PEP or PUPP again. [1,2]
Medscape, Polymorphic Eruption of Pregnancy, https://emedicine.medscape.com/article/1123725-overview
DermNet NZ, Polymorphic Eruption of Pregnancy, https://www.dermnetnz.org/topics/polymorphic-eruption-of-pregnancy