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

BACKGROUND AND OBJECTIVE 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.