Does my daughter have a soy allergy?

Caitlin • Marabelle Grace 5/26/2018 ✨💕

My daughter will be 4 months on Wednesday. I tried breastfeeding her and she could never latch, so I decided to start exclusively pumping. She had a really hard time taking my breast milk. She would get really fussy, have gas, diarrhea, and bloating. We decided to switch her onto Similac Sensitive and she was still having these same issues. Later, her doctor recommended putting her on Similac Alimentum because she suspected a milk protein allergy and she did a complete 180 and everything was great. Her doctor told me that at around 4 months I could start putting rice cereal in her formula. We tried some last night and she sucked it right down, and then again this morning. I was changing her diaper about 30 minutes later and her face was very red and splotchy all around her eyes and mouth. The rice cereal is Gluten Free, Dairy Free, Egg Free, but it contains Soy. I’m wondering now if she has a soy allergy vs a milk protein allergy