I spoke to a client recently whose baby had a very bad rash that I saw when he was two or three months old. She tried everything changing detergent etc. After many tests she found the baby had a zinc deficiency. I didn't know it was the same baby when mom brought him into my WIC class when he was seven months old. She and the breastfed baby had both taken a zinc supplement. I looked it up in the brown bible and found that zinc deficiency can cause rash.. Mom never mentioned stinky stools so I have no idea whether this was also a problem. Judy in Phoenix where the air is cooler outside this morning but not cold enough for frost.