DS is allergic to peanuts
For now anyway. Sorry I haven't updated sooner - there has been little time.
We followed up at the allergist and his skin test for the 10 most popular food allergens came back negative but based on DS's reaction after eating the PB&J, he said to steer clear of peanuts for a year (or until 2 yrs old) and then we'll retest both skin and blood. Apparently, there is a high rate of false negatives with the skin test so close after a reaction.
Fortunately, I asked (well, my MIL asked....) if I could continue eating peanut butter and nurse. Since it hasn't bothered DS, the doc said I could continue. He said we could continue with what had been working for us essentially but just not give DS the peanut products. Easy enough.
So, we are now epi pen owners and I don't eat peanut butter in my own house anymore. 
Re: DS is allergic to peanuts
Hopefully, he'll grow out of it. My niece was diagnosed with a tree nut allergy around 1 or 2. She's five, and was just retested, and grew out of it.
Good Luck. I know that staying away from peanuts is hard!
Allergies suck. My DD is allergic to dairy, eggs, peanut and tree nut. After a little time, managing allergies becomes much easier. We were told by our local allergist to avoid foods when I was nursing, but our "good" allergist at Hopkins said to keep doing what we were currently doing if it hadn't caused a reaction. Good luck to you - hope he outgrows it.