It all starts when your child complains of a sore throat. It doesn't look too inflamed, and conveniently, it happens to bother him on the same day as his spelling test. Do you let him stay home? Or do you risk dropping him off at school and infecting his classmates if he turns out to be contagious? To help you better identify when your kids are at their most contagious and have every reason to take a sick day, take note of some of these tips from the doc herself.