Maria Bernardez, MD, of Orange Pediatric Care provides the answer

Sometimes it can be very frustrating if you go to the doctor sick and you come home only with instructions to take lots of fluids and lots of rest, [and] decongestants and fever reducers sometimes. The Centers for Disease Control recommend that antibiotics only be given for bacterial infections. This is because there is a danger of antibiotic resistance when antibiotics are overused. And the way to know whether it is bacterial or viral is to go see your doctor.