Hi, I have four children and at the beginning of the week they all within a few days came down with a fever, the one is well now but three of them have a itchy rash on the face, hands and feet, I took the youngest one who is thirteen months old to the dr and he said it is a virus but that was before my oldest daughter came up with the itchy rash on her hands face and feet? What types of things cause these rashes?