A report published in Allergy identified the knowledge gaps that should be addressed to appropriately identify patients who have the highest risk of severe food-induced allergic reactions.
Severe allergic reactions can be very similar to mild or moderate reactions at onset, and many individuals who experience life-threatening reactions may not initially realize the potential severity of the reaction. Therefore, Graham Roberts, DM, MSc, from the University of Southampton Faculty of Medicine, Southampton General Hospital, and colleagues reviewed the evidence and examined the factors that could be used to identify patients with the highest risk of allergic reactions.
The most common foods that cause anaphylaxis and fatal anaphylaxis are peanuts and tree nuts. In addition, seafood is also a frequent cause of anaphylaxis and milk allergies in children are a common cause of fatal anaphylaxis. Individuals who experience severe reactions may have immunoglobulin E to certain epitopes that are more resistant to modification in food processing, although this may not apply to all allergens.
The association between the dose of allergen exposure and symptom severity is still unknown. Allergen dose may be a risk factor in a subgroup of patients, but some studies report that individuals with prior anaphylaxis do not have a lower eliciting dose than individuals who report mild allergic reactions. “It is therefore important to consider severity and sensitivity as separate factors: a highly sensitive individual will not necessarily experience severe symptoms during an allergic reaction,” the authors stated.
Patient risk-taking is another critical factor in predicting food allergy severity. Adolescents in particular are prone to eat risky food or to not carry an adrenaline autoinjector device, although more research is required to understand the impact of risk-taking on allergy severity. Other patient behaviors that could affect allergy severity include alcohol use, medication, and exercise.
The authors note that almost 50% of children with a food allergy also have asthma, but almost none of these children will experience a fatal reaction. However, asthma is not in itself a strong predictor of fatal anaphylaxis.
There are currently no validated tests in clinical practice that can effectively identify patients with the highest risk of severe anaphylaxis. The investigators note that additional research should be conducted to understand the interaction of risk factors and to improve risk stratification of patients with food allergies.
“These gaps in knowledge contribute to the allergic individuals’ lack of control over their environment and the resulting impact on their quality of life,” the study authors wrote. “Addressing them will reduce the uncertainty, which is at the root of this anxiety, and thus help in the ultimate goal of improving an individual’s allergy management.”
- Turner PJ, Baumert JL, Beyer K, et al. Can we identify patients at risk of life-threatening allergic reactions to food? Allergy. 2016; doi: 10.1111/all.12924.