My son is 5 months old and has been on every similac formula they make and has had an allergic reaction to all of them. Advanced and Sensitive made him puke waterfalls out his nose and everything, and soy made him spit up frequently along with constipating him really bad...alimentum helps him poop but giving him the powder makes him spit up alot and gives him diarreah and giving him the ready to feed constipates him and with both he spits up alot and has really dry cheeks like leather. I spoke with a specialty doctor who said he needed EleCare made by Abbot and with being on that for 4 days now he hasn't pooped, when he tries its just pebbles and he broke out with a rash from his neck up along with frequent spitting up also. The doctor said that was the last formula we could try but after doing research online I found Enfamil Nutramigen....has anyone had these problems with their little one or tried this formula? I'm stuck and don't know what else I could do for my little guy so any advice will help!!