My son was diagnosed by his physician with a strep rash appearing all over his body. He was prescribed penicilin and it went away. Two weeks later which is today it came back in the bath tub. Itching at first on his buttocks then appearing on the arms,chest,back of leg creases & neck very rapidly. Is this an allergy or really strep or maybe scarlett fever?? Sometimes reading on the net can get scary! If anyone has an idea of what this could be please reply. Thanks for your time.