The rising prevalence of food allergies poses a major global public health challenge. As dietary habits worldwide continue to change, there is an urgent need to update our understanding of specific allergenic triggers, especially tree nuts. While nuts like peanuts and hazelnuts have long been identified as key offenders, detailed data on less-studied allergens such as cashews remain limited. This recent extensive analysis from the European Anaphylaxis Registry, published in the journal Allergy, aims to fill this gap by providing a comprehensive overview of the epidemiology and clinical characteristics of tree nut-induced anaphylaxis (TIA) across Europe.
The study involved extracting and analyzing cases of TIA spanning nearly two decades, from 2007 until April 2024. Out of 5,945 registered food-induced reactions in the registry, TIA accounted for a substantial 1,389 cases, or 23% of the total. For an in-depth clinical analysis, researchers focused on 1,083 cases where the specific allergenic trigger was confirmed. This cohort comprised a significant majority of children (845 cases, with a median age of 4 years) and 238 adult patients (median age of 38 years), allowing for a detailed age-stratified examination of sensitization patterns and reaction severity.
The findings for the pediatric population reveal a significant shift in allergic trends. The data identify cashew as the most common cause of anaphylaxis among children, surpassing previously common triggers like hazelnut and walnut. Cashew accounted for 334 cases in this pediatric group, and its proportion relative to other tree nut reactions showed a notable, concerning increase from 2007 to 2024. Adding to this concern is the observation that cashew-induced reactions were often triggered by very small amounts of the nut, sometimes less than a teaspoon, highlighting its potency as an allergen and the high risk of accidental exposure.
In the adult cohort, while hazelnut and walnut remained frequent elicitors, the study highlighted an unexpected and significant risk from almond. Almond-induced anaphylaxis was notably prevalent among adults, prompting a call for closer surveillance of this nut. Unlike children, adults reacting to tree nuts typically required a larger amount of the allergen to trigger a reaction. Furthermore, adult patients were far more likely to have potential cofactors—such as physical exercise, co-morbid illness, or non-steroidal anti-inflammatory drugs (NSAIDs)—present at the time of the reaction (50% of adult cases vs. 17% of children’s cases), indicating a distinct clinical pathway for adult-onset TIA.
A key deficiency identified by the registry data was the overall low level of patient preparedness and proper emergency management. Across both age groups, most patients were unaware of their allergy before the anaphylactic event, with prior diagnosis rates around only 20%. This lack of awareness led to a significant underuse of life-saving medication. The use of epinephrine in lay treatment was notably low, recorded in only 13% of children and just 3% of adults. Although medical professionals administered epinephrine more often, its use still reached only about 40% of cases, highlighting a systemic failure to follow established anaphylaxis guidelines.
In conclusion, this comprehensive European analysis confirms that cashew has become the leading cause of tree nut anaphylaxis in children—an upward trend that calls for immediate and effective prevention strategies. At the same time, the common role of almonds in adult-onset reactions highlights the need for increased monitoring as an emerging risk. Most importantly, the findings reveal significant gaps in acute allergy management, especially the low rate of prior diagnoses and the concerning underuse of epinephrine auto-injectors. Addressing these knowledge gaps and enhancing adherence to acute management protocols are essential for reducing morbidity and mortality related to severe tree nut allergies.his comprehensive European analysis confirms that cashew has become the predominant cause of tree nut anaphylaxis in children, an increasing trend that demands immediate and effective prevention strategies. Simultaneously, the frequent role of almond in adult-onset reactions signals a need for its enhanced monitoring as an emerging risk. Most crucially, the findings expose significant shortfalls in acute allergy management, particularly the low rate of prior diagnosis and the alarming underuse of epinephrine auto-injectors. Addressing these knowledge gaps and improving compliance with acute management protocols is paramount for minimizing morbidity and mortality related to severe tree nut allergies.
