Anaphylactic Shock after Insect-Sting Challenge in 138 Persons with a Previous Insect-Sting Reaction

Main Results: Only 39 of 138 (28%) of patients with a previous insect-sting anaphylactic reaction developed anaphylactic symptoms after sting challenge. Values of cardiovascular mediators and mean arterial pressure did not differ after the challenge from initial values in the volunteers or in the patients with a mild or no reaction after challenge. In the 17 patients with anaphylactic shock, mean arterial pressure decreased from 97 +- 11 (mean +- SD) to 65 +- 17 mm Hg (P < 0.001), epinephrine levels rose from a median of 0.3 nmol/L (range, 0.2 to 2.3 nmol/L) to 2.5 nmol/L (0.2 to 35.7 nmol/L; P < 0.05), norepinephrine from 1.5 nmol/L (0.5 to 6.7) to 5.9 nmol/L (1.6 to 30.9 nmol/L; P < 0.01), and angiotensin II from 61 pmol/L (7 to 217 pmol/L) to 105 pmol/L (11 to 286 pmol/L; P < 0.01), all within 5 minutes after the onset of anaphylactic symptoms. The rise of these mediators correlated with the drop in blood pressure (P < 0.001). Dopamine and angiotensin I levels did not change in any participants.