A 23-Year-Old Woman Comes to the Emergency Department Because of a Diffuse

A 23-year-old woman comes to the emergency department because of a diffuse, itchy rash and swollen face for 6 hours. That morning, she was diagnosed with an abscess of the lower leg. She underwent treatment with incision and drainage as well as oral antibiotics. She has no history of serious illness. She is not in acute distress. Her temperature is 37.2°C (99°F) , pulse is 78/min, and blood pressure is 128/84 mm Hg. Physical examination shows mild swelling of the eyelids and lips. There are multiple erythematous patches and wheals over her upper extremities, back, and abdomen. The lungs are clear to auscultation. Which of the following is the most likely cause of this patient's hypotension?

A) Chemical mediator-induced decreased myocardial contractility
B) Chemical mediator-induced increased vascular permeability
C) Impaired endogenous sympathetic nerve activity
D) Toxin-mediated decreased myocardial contractility
E) Toxin-mediated increased capillary permeability