What Is The Treatment For Skin Rashes All Over The Body?

My college Daughter, is complaining of an all body rash around her trunk, legs, arms, back and her neck. its itches and has a oblong red circular apperance. She had her Wisdom teeth pulled a month ago and has been complaining ever since of this rash.. what could it be? Also she has had a severe cold two week after her wisdom teeth were removed.