A 37-Year-Old Man with a Febrile Illness

A 37-year-old man with no significant past medical history presented to the emergency department with a 4-day history of an abrupt febrile illness associated with a burning sensation of the palms and soles, myalgia, nausea and vomiting, and shortness of breath. Images of his left eye obtained at hospital admission (figure 1) and 4 days later (figure 2) reveal clues to the correct diagnosis. What is the diagnosis, and how was it made?