When your child has a skin rash, it can be difficult to know whether to call the pediatrician or wait. Here are some guidelines to help you decide. If the rash is not bothering your child and it goes away in a few days, it usually isn't a reason to worry. However, if the rash persists for more than a few days or is accompanied by a fever, you should call your doctor. A rash with a fever could signal an infection. Other symptoms that warrant a call to your pediatrician include: difficulty breathing, a bluish color around the lips or nails, dehydration signs like no tears when crying, or red or black color in the poop or vomit. If your child's illness seems mild enough to wait until morning, keep a journal of symptoms and questions for the pediatrician. This will help guide your conversation with the doctor. Always trust your instincts; if something doesn't feel right, it's better to call your pediatrician.