Pruritic Urticarial Papules and Plaques of Pregnancy has many names. I call it PUPPS of pregnancy. Others abbreviate it PUPPP. In the UK it is also known as PEP (polymorphic eruption of pregnancy). No matter what you choose to call it, PUPPS is basically a pregnancy rash.
There are many speculations as to why PUPPS happens but none have been proven yet. There was a study that showed that 70% of expectant mothers with PUPPS were carrying boys. Some researchers think it has to do with male DNA interacting with the mother's body causing irritation. Since I had a girl when I had PUPPS, I do not think this is the primary reason for the pregnancy rash. Although we do not know the exact reason, we do know that it has nothing to do with autoimmune diseases, pre-eclampsia, hormones, or fetal abnormalities.
The PUPPS rash starts in the stretchmarks of the stomach and breast areas. After the initial rash appears, it will then start spreading to the arms, legs and buttocks.
PUPPS is not commonly diagnosed with a biopsy or blood tests. It is usually diagnosed by the appearance of the rash itself. My doctor didn't know what my rash was. She had to look up a picture in her PDR (Physician's Desk Reference) to make a diagnosis. Since the rash only occurs in about one out of every 200 pregnancies, I didn't fault her for not knowing what the rash looked like. I was just thankful to know what it was.
There are no known lasting effects of the PUPPS rash. I have a few faint scars from scratching too much. Do Not Scratch The Rash! Other than that, I have never heard of any case where PUPPS had harmed the mother or the fetus. The rash should go away a few days after delivery. The itching will stop even sooner than that (yay!) If you are worried about getting the rash again...don't. This rash typically occurs only in a first pregnancy. The odds of having PUPPS during a second pregnancy are rare.
Do your best to focus on the outcome and not the mild speed bump known as PUPPS.