What Causes Itchy Blisters On The Boot Of The Feet?

When I was pregnant in my 3rd trimester I got little blisters like bumps in between my fingers and the back of my hands.. first they would start off as little red bumps and when I would scratch they turned into blisters almost like ecxima.. I also got the same thing on my left foot only, it started with little red bumps and also turned into little blisters almost the size of a white head pimple, the liquid inside was clear though.. (on the top of my foot) but on the bottom of my foot the blisters where Really big and the liquid looked like it had a yellow tint and if I tried to pop it the skin under the blister looked really red sometimes on the big ones.. in just trying to figure out what this is.. it also seemed like it was mixed with foot fungus or something because the more I scratched the worse it got and it was so itchy I couldn t stop scratching.. my skin on my bottom of my left foot turned purple and hard like a big purple scab it was so weird.. one day the scab cracked and I can see the inside of my skin didn t look normal it was scarry! It was black/purple I went to the ER and none of the doctors could tell me what was going on.. it went away about 2 weeks before I delivered.. now I am 3 months post partum and my feet are itching again! This time I m not scratching but I have a little blister on the bottom of my foot :/ it was scarry! Dose anyone know what it could be? How to cure it? Prevent it? Has this happened to anyone else?? :/