A couple of weeks ago I gave my son the Gerber Oatmeal with Bananas with water since I didn't have any breastmilk to mix it with. He got an ugly diaper rash the next day and it took about a week's time for it to go away. Does this mean that he can be allergic to oatmeal? It's a little confusing because he's had the same oatmeal before without any rash -but when he had it before it was with breastmilk. What do you ladies think?