Risk Factors in Severe Anaphylaxis: Which Matters the Most, Food or Cofactors

Background: The prevalence of anaphylactic shock, the most severe manifestation of anaphylaxis, remains unknown. Risk factors and biomarkers have not been fully identified. Objective: To identify risk factors in patients who experience anaphylactic shock. Methods: Using lipid transfer protein (LTP) allergy as a model, we compared the characteristics of patients who developed anaphylaxis and anaphylactic shock. We recorded demographics, pollen sensitization, foods ingested up to 2 hours before onset of the reaction, and the presence of cofactors. Culprit foods were identified through a compatible clinical history and positive allergology work-up (skin prick test and/or sIgE). Results: We evaluated 150 reactions in 55 patients with anaphylaxis (134 reactions) and 12 with anaphylactic shock (16 reactions). Patients in the anaphylaxis group experienced twice as many reactions (mean [SD], 2.4 [2.5] for anaphylaxis vs 1.3 [1.5] for anaphylactic shock; P<. 02). No relationship was found between any food group and severity of the reaction. The most frequent food involved in both groups of patients was the combination of several plant-derived foods (plant food mix), followed by peach and nuts. Indeed, in the reactions caused by plant food mix, the presence of a cofactor was observed more often than in other food groups. On the other hand, cofactors were not present in peach- and nut-related reactions. Exercise was the most frequent cofactor in all groups. Conclusion: In our series, the severity of the reactions was not determined by the kind of food or presence of a cofactor. Anaphylactic shock seems to be an infrequent presentation that may be associated with other individual-related factors requiring further evaluation.

Automated summary

The study aimed to identify risk factors in patients who experience anaphylactic shock. Using lipid transfer protein (LTP) allergy as a model, the characteristics of patients who developed anaphylaxis and anaphylactic shock were compared. The results showed that patients in the anaphylaxis group experienced more reactions than those in the anaphylactic shock group. There was no relationship between different food groups and the severity of the reaction. The most frequent food involved in both groups was a combination of several plant-derived foods. Anaphylactic shock seems to be associated with other individual-related factors requiring further evaluation.