Hi -I think my 9 month older daughter has FPIES. After a few severe vomiting incidents (including one that led us to call 911) and a google search for "barfs solid food" I discovered FPIES, and have met an allergist who thinks she indeed has FPIES. From piecing things together, it seems like her triggers are avocado and peanut butter and possibly rice and oats. All of the FPIES reactions started after multiple exposures to each trigger. We have just started food trials, with our doctor recommending we start with spinach. On the first day of spinach she had some spit up ~10 hours after eating one bite - it made me nervous but i convinced myself it was just a coincidence (she doesn't spit up often). Today was our fourth day with spinach and she had what to me seems like a minor FPIES reaction, 3 spit-up/barfs 3 hours after eating two small bites of spinach and she was very tired acting for several hours. Very disappointing... our Dr. said she had never seen a spinach "fail" which was even more disheartening. The next food we are supposed to try is broccoli but I am not sure how soon to wait in between - the Dr. said 3 days but I wonder if she needs longer? I am curious if others have experienced this sort of mild reaction after a very small dose of a food? Also, I am also concerned about my daughter getting proper nutrition and was wondering if there is a multivitamin / iron source that others have found successful with FPIES babies? Her Dr. prescribed the Enfamil drops and she immediately spit it up - just because of the taste I think. The Dr. then suggested pur absorb iron water but I realized I don't see how I am going to get her to drink that much iron water...
Well, I don't know all of the answers to your questions. We didn't do very well with any solid food at nine months old. We relied on breastfeeding, Gerber baby food (excluding his trigger foods of course) and baby oatmeal (surprisingly a safe food). He did super well at that stage.
We didn't introduce most real adult food until about a year old, and it is going quite slowly. We do have a multivitamin that works for us- Poly-vi-sol with or without Iron (mixed with baby food- which we still use in his diet because applesauce is a fail). BUT, every baby with FPIES is different- so it would need to be trialed.
Our food trials are 1-2 weeks with after a month we label as "safe." We range from mild to severe reactions depending on the amount, how it is cooked, how many exposures, etc.
Hope that helps!