ANAPHYLACTIC SHOCK AFFER INSECT-STING CHALLENGE IN 138 PERSONS WITH A PREVIOUS INSECT-STING REACTION
Purpose of the Study. The goal of the study was to establish the frequency with which anaphylactic reactions reoccur after sting challenge in persons with previous insect-sting anaphylactic reactions, as well as the relation between the severity of anaphylaxis and levels of catecholamines and angiotensins. Methods. One hundred thirty-eight patients with a history of an anaphylactic reaction and eight normals (including five patients who had been previously stung) were subjected to provocation test with the relevant insect. Blood samples were collected and assayed for epinephrine, norepinephrine, dopamine, and angiotensin I and II levels. Findings. "Only" 39 of 138 (28%) patients with a previous insect sting anaphylactic reaction developed anaphylactic symptoms after sting challenge. Only those with a history of a severe reaction developed anaphylactic shock. No change in cardiovascular mediators or blood pressure was seen in patients with no or mild reactions, while those patients with anaphylactic shock had a mean arterial blood pressure drop of 33%. Significant increases in epinephrine, norepinephrine, and angiotensin II were observed within 5 minutes after the onset of symptoms and were strongly correlated with a drop in blood pressure. Dopamine and angiotensin I levels did not change significantly in any participants. Reviewers' Comments. The repeat rate of systemic reactions of 28% is substantially lower than the previously reported rate of 60% (Hung KJ, et al. NEJM. 1978;299:157). Unfortunately, the present study does not provide significant information regarding the study population, particularly the time lapsed between the original and rechallenge stings. We are all aware of the associated problems of beta-blockers and anaphylaxis.