Factors predicting anaphylaxis in children with tree nut allergies.

Background: Tree nut (TN) allergies are the most common cause of fatal anaphylaxis and generally are ongoing food allergies throughout life. Objective: To investigate the predicting factors for TN anaphylaxis in children.
Methods: Children with TN allergy were divided into anaphylactic and nonanaphylactic groups, those who had an anaphylactic reaction with at least one type of TN and those with any type of reaction other than anaphylaxis with TNs, respectively. Children with TN allergies were evaluated for the predictors of anaphylaxis by using multivariate logistic regression analysis.
Results: A total of 184 children (ages 4.9 years; 3.2-6.9 years) with TN allergy were included in the study. Of these, 90 experienced an anaphylactic type of reaction on exposure to at least one type of TNs. Comparisons of the two groups showed that concomitant asthma, skin-prick test, specific immunoglobulin E, total immunoglobulin E, and serum basal tryptase (sBT) levels were significantly higher in the anaphylactic group compared with the nonanaphylactic group. In multivariate analysis, female gender (odds ratio [OR] 4.905 [95% confidence interval {CI}, 1.266-19.001], p = 0.021), sBT levels (OR 2.287 [95% CI, 1.431-3.654], p < 0.001), concomitant egg white allergy (OR 4.135 [95% CI, 1.016-16.481], p = 0.048), and concomitant asthma (OR 3.874 [95% CI, 1.109-13.526], p = 0.034) were risk factors for anaphylaxis. The optimal cutoff value for sBT was 2.06 ng/mL, with a sensitivity of 85.9% and a specificity of 69%, as well as an area under the curve 0.810 (95% CI, 0.717-0.903, p < 0.001). The sBT levels of 1.94 ng/mL and 5.30 ng/mL predicted clinical reactivity at 50% and 95% probabilities.
Conclusion: Different aspects, including gender, higher mast cell load and/or activation, and a stronger atopic background (e.g., coexisting egg allergy, asthma), contributed to the development of anaphylactic reactions to TNs in children.