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

Abstract

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 anaphylactic shock patients. Methods: Using lipid transfer protein (LTP)allergy as a model, the characteristics of patients who developed anaphylaxis and anaphylactic shock were compared. Demographics, pollen sensitization, foods ingested up to 2 hours before the reaction onset, and the presence of a cofactor were recorded. Culprit foods were identified by compatible clinical history and positive allergological work-up (skin prick test and/or sIgE). Results:150 reactions were evaluated, suffered by 55 patients with An (134 reactions) and 12 with AnS (16 reactions). Patients in the anaphylaxis group experienced twice as many reactions (mean [SD] 2.4[2.5] in An vs 1.3[1.5) in AnS, p<0.02). No relationship between any food group and reaction severity was found. 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 “plant food mix” reactions the presence of a cofactor was more often observed than in other food groups. On the other hand, cofactors were not present in peach- and nuts-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 an infrequent presentation that may be related with other individual-related factors that need further evaluation.