A 72 year-old male came to your urgent care clinic complaining of maculopapular skin rash, nausea, anorexia,jaundice, watery diarrhea, abdominal pain for the last one week. His medical history is significant for receiving an allogeneic hematopoietic cell transplantation four weeks ago for multiple myeloma. In the physical examination, you noticed blistery maculopapular rash all over his body, sparing the scalp. Laboratory results are remarkable for hyperbilirubinemia. What is the most likely diagnosis in this patient?
