What if my baby has a rash on his belly?
Evaluate the emergency: If the rash is red or pink-red, press on it; if it blanches and refills when you release, chances are it's not dangerous. If you can't make it turn white by pressing into the skin that could mean there's bleeding into the skin, and "that's the type of rash you see with dangerous infections or other serious illness, so call your pediatrician," says Dr. Baker. A rash that does blanch is less worrisome, but it's best to have your doctor take a look if it doesn't go away within a few days.
Go to the ER: Hives -- raised, itchy welts -- are a sign of an allergic reaction. Call 911 if his lips are swollen, he's wheezing, or he has trouble swallowing, speaking, or breathing.