Know Thyself

A patient with leukemia undergoes an allogeneic hematopoietic stem cell transplant and is discharged on cyclosporine and tacrolimus. He presents to his followup appointment one week later with the arm shown above. He initially thought he had a sunburn on his neck, ears, shoulders, palms, and soles, but then it progressively got worse. It changed from an erythematous maculopapular rash to a confluent swelling with bullae. Review of systems is positive for severe diarrhea and abdominal cramping. The bowel movements started as watery but progressed to bloody. Liver enzymes show an elevated bilirubin and alkaline phosphatase.

Challenge: What's your diagnosis?

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