Investigation of the factors that determine the severity of allergic reactions to Hymenoptera venoms.

Introduction: Many risk factors that facilitate venom allergy and increase systemic reaction severity have been described in various studies, but the data are limited regarding this issue. We aimed to evaluate the impact of total immunoglobulin E (tIgE), specific IgE, and tryptase levels on the severity of systemic reactions in patients with a history of allergic reactions to Hymenoptera stings. Method: Eighty-two patients with a history of allergic reaction to Hymenoptera venom admitted to our outpatient clinic between March 2016 and August 2017 were included. Venom-specific IgE (Apis mellifera and Vespula vulgaris), total IgE, and basal tryptase levels were measured. Skin-prick tests were performed with inhalant allergens. The levels of specific IgE, total IgE, and tryptase were compared between patients with large local reactions and systemic reactions, and the relation of these parameters with the severity of systemic reaction was evaluated. Results: There were no significant differences in the specific IgE, total IgE, and tryptase values in patients with large local reactions and a history of systemic reactions (p > 0.05). The age, basal tryptase, and V. vulgaris-specific IgE levels of patients with a grade IV reaction history were higher than those with grades I-III reaction history (p < 0.05). An important finding was that high basal tryptase levels were a risk factor for grade IV reactions (p = 0.047, χ² = 4.512). There was a strong positive correlation between total IgE levels and V. vulgaris- and A. mellifera-specific IgE values in patients with a grade IV reaction history (r = 0.94, p = 0.005; and r = 0.88, p = 0.021, respectively). Conclusion: Baseline serum tryptase levels were a risk factor for the development of severe systemic reactions in venom allergy. This risk increases with increasing age in these patients. Another notable finding was the correlation between total IgE and venom-specific IgE values in patients with severe systemic reactions.