Fever and Rash in a Traveler.

This Photo Quiz article presents a case of acute dengue fever in an American traveler returning from Puerto Rico. In addition to the relevant epidemiologic and medical history, a key finding that allowed clinical diagnosis of the infection was the characteristic rash ("isles of white in a sea of red") that our patient manifested. This physical exam finding was documented and is featured prominently in the article. Despite the fact that initial testing for dengue virus infection was negative, the characteristic exposures, incubation period, and clinical syndrome our patient presented with allowed us to provide directed care for the most likely illness. Our clinical diagnosis was later confirmed on convalescent serologic testing. We use this case to illustrate and discuss highlights of diagnosis, treatment, and prevention of both non-severe and severe dengue virus infection.