Approximately 10 minutes after being stung on the right lower leg by a yellow jacket (a type of wasp), a 45-year-old man began to feel light-headed and nauseated. He called emergency medical services, and paramedics arrived 10 minutes later. They found him to be alert but anxious, with scattered areas of erythema on his trunk and a small, localized area of tenderness, swelling, and erythema . . .