Hi, I think this baby should be seen by the doctor to see what the rash
really looks like. If it is hives, it is likely a reaction to something
new, like the amoxicillin, that seems the most obvious to me. Hives are
more likely to flare when one is having a reaction when one's body gets
very warm, such as when breastfeeding or taking a warm bath. I have limited
info, but I vote drug reaction and increased hives when cuddling with
mom.-Anne Eglash MD and mom of a girl very allergic to many antibiotics