Diagnoses in the order of “most likely” to “possible but unlikely”

  A 17-year-old male presents with a complaint of a red, itchy rash over his torso and back x 1 week, which is keeping him up at night. He denies sick exposures or recent visit to wooded areas. He denies other symptoms, significant history or allergies. Describe three (3) questions, in order of importance that you would like to ask this patient and give a brief explanation of why? From the information provided, list your differential diagnoses in the order of “most likely” to “possible but unlikely”.