it could be fifths......my son had it a few years ago .....he had a fever and sore throat and a bright red rash on his face that looked like he had been slapped. its very contagious and dangerous if your pregnant in the first trimester. I find it very strange that a dr would diagnose over the phone.....I have a 24 hour exclusion for rashes of any kind, and a 48 hour exclusion for any ailment that requires antibiotics