ABSTRACT

A father brings his 12-year-old boy to the emergency department after noticing a diffuse, pruritic rash that began on his trunk and has since spread “all over his body.” The patient is generally comfortable with normal vital signs and otherwise the physical exam is unremarkable. The patient's father tells you that his son is otherwise healthy—except for an “infected lymph node” that his pediatrician has been treating with Bactrim (brand name for trimethoprim/sulfamethoxazole [TMP/SXT]) for the last week.