A 23-year-old woman prese...

A 23-year-old female presented to the emergency department with a 1-day history of an itchy rash. Five days before presentation, fevers, chills, myalgias, nausea, anorexia, and a retro-orbital headache had developed. The symptoms lasted 4 days and had abated before presentation. Vital signs were normal. A physical examination was notable for a non-blanching, maculopapular, erythematous rash surrounding scattered patches of unaffected skin on the arms (Panel A), legs, and trunk (Panel B). The palms and soles were spared. There was no bruising or petechiae. A complete blood count showed leukopenia with lymphopenia; the platelet count was normal. Results of a rapid test for the dengue nonstructural protein 1 and serologic testing for dengue IgM were positive. A diagnosis of dengue was made. 
Dengue infection is classified into three phases: febrile, critical, and convalescent. In the convalescent phase of infection, a confluent, erythematous rash with small areas of unaffected skin that look like “islands in a sea of red” may be present, as seen in this patient. The patient was reassured that her condition would continue to improve. Three days later, her rash had completely resolved.