If your baby develops a rash while having a fever, it is likely that he or she is suffering from a rash illness. Most rash illnesses are caused by viral infections, which can often be determined by blood tests and C-reactive protein. For example, C-reactive protein is normal and white blood cells are often lower or normal. The baby can be treated with antiviral drugs, which are more effective, such as oral ribavirin pellets and busulfan anti-inflammatory oral solution. If the itchiness is accompanied by the bun, the child can be given a local application of glyburide lotion or oral anti-allergy medicine, which can effectively stop the itch. For fever, if the temperature is high, more than 38.5 ℃, oral antipyretic drugs are needed.