@Mae: really good point. I remember my sons allergist mentioned that repeated exposure through the skin rather than the gut could be a big factor. I'll at least know this time not to eat a PB sandwich and then grab the baby. (Can't anyway because I need to be very careful with my son around. We don't keep any nut products in the house now...)
@MrsH: glad you are getting some good support here! I would/do feel exactly the same in your case. Part of the reason I stopped BFing #1 pretty early was because I couldn't pinpoint his eczema causes and couldn't figure out all of the possible dietary triggers and whether it was worth it to try to care for a newborn, work, pump etc while carrying out my own elimination diet. I know there are other causes for eczema sometimes but I tend to put a lot of pressure and blame on myself (to a fault probably).
Cheese is also pretty much my fav thing and number one protein source so cutting it out in the early days would've meant I was pretty much living on dry raisin bran.