A decision rule determined by using a Challenge Severity Score (CSS) may help predict the risk for severe reaction during peanut oral food challenges (OFC), according to the results of a study published in the Annals of Allergy, Asthma & Immunology.
The prevalence of food allergies, and in particular peanut allergies, has increased worldwide in recent years. In the United States, approximately 200,000 emergency department visits and hospitalizations occur each year as the result of food-induced anaphylaxis. However, diagnosis of these food allergies can be complex. The results of skin prick tests are not definitive, and the gold standard for determining a food allergy is the double-blind, placebo-controlled food challenge. However, these challenges involve a risk for systemic and even life-threatening reactions. Thus, the development of tools to stratify patients by potential risk for severe reactions during peanut OFC is of great importance.
R. Sharon Chinthrajah, MD, of the Sean N. Parker Center for Allergy and Asthma Research at Stanford University and the Department of Medicine and Department of Pediatrics, Stanford University School of Medicine in California, and colleagues obtained the medical history and allergy test results for 120 patients with peanut allergy who underwent double-blind, placebo-controlled food challenges. Reactions were assigned a CSS from 1 to 6 based on cumulative tolerated dose and a “severity clinical indicator.” The researchers considered demographic characteristics, clinical features, peanut component immunoglobulin E values, and a basophil activation marker in a multistep analysis to determine a flexible decision rule to establish risk for reaction during peanut OFC.
A severe reaction — CSS >4 — occurred in 18.3% of participants. The decision rule identified 3 variables, given in order of importance, as predictors of reaction severity: ratio of %CD63hi stimulation with peanut to %CD63hi anti-immunoglobulin E (CD63 ratio), history of exercise-induced asthma, and forced expiratory volume in 1 second/forced vital capacity ratio. The CD63 ratio was a strong predictor of CSS on its own.
The authors argued that further testing of this decision rule is needed before it can be used in clinical practice.
Chinthrajah RS, Purington N, Andorf S, et al. Development of a tool predicting severity of allergic reaction during peanut challenge [published online April 27, 2018]. Ann Allergy Asthma Immunol. doi:10.1016/j.anai.2018.04.020