Pregnancy rash

So I'm just about halfway through the 17th week and my skin has become uber sensitive. I break out in an itchy heat rash that leaves me with a patch of dry skin whenever I wear clothes that aren't completely loose and at least 50% cotton. It's on my belly and my legs. I discovered this when I made the dreadful mistake of wearing pantyhose a few days ago. My legs look awful!! Is anyone else having rash issues? I have heard of a rash associates with pregnancy called PUPP.  I'm going to ask the doctor this Friday if that could be what is causing my rash, but: I also heard a pregnancy rash called PUPP usually means a baby boy.  Was curious if any mothers out there that have had PUPP have any thoughts on this ole wives tale!