Derm Dx: A rash response to southern exposure

A 28-year-old Hispanic man presented with a 10-month history of a pruritic rash on his right flank (Fig 1). One to two weeks prior to noticing the lesion, he had spent five days in Arizona. The lesion had doubled in size in one month, according to the patient. He had no history of similar rashes or lesions and was otherwise ...