Burning Rash - Please Help!

I had twins five weeks ago and have been having an ongoing problem with a rash.  When I was about 31 weeks pregnant I developed a red, burning rash over about 90% of my body).  It looked like the worst sunburn I could imagine and was truly the worst pain I have ever experienced - it felt like I was on fire. It was particuarly bad on my neck, back, arms and chest.  I was on bedrest so it obviously wasn't a sunburn!  My OB ruled out PUPPs and sent me to a dermatologist who over the next two weeks prescribed a number of sterioid shots, creams and a "med" pack, but nothing really made it better.  I went into pre-term labor at 34 weeks and ended up having an emergency c-section.  By the time I was back in my room 3 hours after surgery the rash was basically gone.  My OB said I had an extremely large placenta and had most likely developed an allergy to it.  Last week (about 4 1/2 weeks post partum) I developed a similar rash over my neck, shoulders and chest.  It isn't quite as bad as the original rash, but is still incredibly painful.  Also, unlike a sunburn, it doesn't hurt any worse to touch it.  I went back to the dermatologist yesterday and she gave me a cortizone shot and prescribed steroid cream.  It's only been about 24 hours, but it is not getting better.  Has anyone had anything like this???  Honestly, I have been happily caring for twins over the past several weeks, but this rash has reduced me to a tearful mess.

[AnnieBrooke]

If it is really an allergic reaction to placenta, do you think there is any possibility that you have any placental tissue left and are reacting to it, or (conversely) are pregnant again?