Switching from soy formula to regular milk

Tweet

My son has had to be on Soy formula basically from the start. Awhile back they said I could try to switch back to regular milk based formula to see how he did (he was on the soy because on regular his reflux was worse) and so he was on milk based for about 3 days and then developed a rash all over his body. So I took him to the emergency room and he was fine. So we switched back to the soy. Now they said when he's ready for milk just to switch him to whole cows milk. But is that really okay? I am afraid of another reaction. I wonder if switching him to soy is better since that's what he's used to. What would you do?