I nursed my daughter exclusively until she was 6 months old. My goal with to stop nursing and start formula and solids around 6 months.
At around 5 1/2 months I gave her cereal for the first time. I figured since I was eventually going to transition her to formula that I would mix her cereal with formula. Milk-based formula that is (I didn't even know that most formula is milk-based). I knew better than to try two things at once but you start thinking and over thinking things. And this is what I decided on. The feeding went really well. Most fell out of her mouth and she was making yum sounds as she ate the cereal Daddy was taking pictures. She probably ate about 2 tsp total. Then after about 5 minutes she started rubbing her chin and it turned red. We stopped the feeding and she ballooned up. Her face nearly tripled in size. As an allergy sufferer myself I worried about her throat closing up. About five minutes later after we had stripped her clothes off her and gently wiped her chin I realized that she had hives (something I had suffered with throughout the years, too). I called the doctor who couldn't really tell me what the cause was -- he said it could be the rice or it could be the formula and I wouldn't know until I tested them separately.
I waited over a week to try cereal with her again. No reactions, so I concluded it was a milk allergy. It was almost two weeks until I gave her Nutramigen formula, an expensive milk-free formula. I wasn't even going to gamble with a soy or other lactose free formula. I figured I could always try them later.
That was how I found out my daughter is allergic to milk. I did eat milk and dairy throughout the whole pregnancy and the entire time I was nursing. The first thing I learned about this allergy is that there is no rhyme or reason to it. Well, at least I know I won't be able to figure it out.
A little update
3 years ago