A Curious Rash

Abstract

A 16-year-old boy presented because of the occurrence of a nonpruritic rash involving mainly the trunk. He had a fever and sore throat the previous week, for which he began antibiotic therapy (amoxicillin-clavulanate) for 7 days, without any improvement. As a result, at 2 days before admission to the emergency department, therapy had been switched to ciprofloxacin. On physical examination, he was febrile (38 C) but in good general condition. He had pharyngitis with laterocervical lymphadenopathy and a morbilliform rash involving the neck and both arms, with spread to the entire trunk (Figure 1), sparing a rectangular area at the left side (Figure 2), where up to 4 days earlier he had applied an anti-inflammatory patch (diclofenac) for back pain. The diagnosis of infectious mononucleosis was confirmed a few days later on the basis of Epstein-Barr virus–specific IgM and IgG antibodies.