Disseminated vaccinia false alarm.

We report the case of a 6-year-old girl who presented in December 2002 with fever and a vesicular rash. Initially she was diagnosed with Stevens-Johnson syndrome. The differential diagnosis was expanded, however, when an exposure to a person who was believed to be vaccinated recently against smallpox was revealed. We describe the sequence of events that ensued and the workup for a possible case of disseminated vaccinia.