Derm Dx: A red and itchy rash after a vacation

A 37-year-old Caucasian man presents to the emergency department with a red and itchy rash for the past 7 days. He states that he recently returned home from a week-long spring vacation on the Florida coastline. It was his first full sun exposure in a year. He noticed his symptoms 3 days after arrival, which he describes as a raised ...