Childhood- vs Adult-Onset Food Allergies

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“What is food to one man, may be fierce poison to others.” - Lucretius (99-55 BC)

Food allergies affect an estimated 4% of children and 1% of adults globally, with prevalence increasing over the past two decades. According to pediatricians, food allergies in children are diagnosed based on the clinical context of manifestations in the skin, respiratory system, and cardiovascular system.

Why does age matter in allergy consultation? Age often determines the standardized formats used by pediatricians, physicians, family physicians, allergists, and dietitians to help formulate a diagnosis and plan further management for the allergic patient. Age-specific standardized allergy history takes into account all the events and history related to the allergic reaction. For children especially, this involves a personal family history of allergies.

Childhood-Onset

Dr. Ruchi Gupta, a professor of pediatrics at Northwestern University, was quoted by Naseem Miller in the Journalists Resource stating that nearly 1 in 5 children with food allergies go to the emergency room for an allergic reaction. How do we know when a child is developing food allergies? While researchers have yet to determine definite causes for the past couple of decades, there are some risk factors that have been widely used to predict the possibility of developing food allergies. Children with moderate to severe eczema may be more susceptible to food allergies. Exposure to antibiotics early in life, births by cesarean section, and urban living are other contributing factors that add to a child’s risk for developing food allergies.

Adult-Onset

Dr. Ruchi Gupta is also the founding director of the Center for Food Allergy and Asthma Research and says that milk and egg allergies resolve in children as they get older, while peanut, tree nut, and shellfish allergies usually last throughout life. Is this why adult-onset food allergies are concerning? Scientists don’t often understand how co-occurring conditions contribute to whether children outgrow allergies or develop new ones. Research presented at the American College of Allergy, Asthma and Immunology Annual Scientific Meeting suggests that when eczema begins may influence a child’s ability to outgrow food allergies. Again, research has usually seen the interplay of genes and environment, but specific factors, like gender differences in the ability to develop an allergy, are still inconsistent. There is consideration that the less exposed you are to a potential allergen, the more likely it will later emerge as a new problem. Dr. Camelia Hernandez tells Harvard Health Publishing, “You really can develop an allergy at any time.”

Investigations in Food Allergies

So, what tells you if you’re allergic to a food item? The following information is common to the food allergy community (and listed in the Journalists Resource), but it is always important to speak to your physician about any adverse reaction to food that you’ve had. There are 2 forms of allergic testing that are common for both children and adults: in vivo and in vitro. The skin prick test is the most common in vivo test, where allergen extracts are placed on the skin and scratched with a lancet. If the skin swells 3 millimeters or more after 15 minutes, there is an indication of a possible clinical allergy. A common in vitro test is the allergen-specific IgE, which is a blood test measuring sIgE in the serum content of the blood. The Oral Food Challenge (OFC) is a test not available to all patients because it involves a patient eating small doses of the suspected allergen. The test involves a physician, a nurse, and rescue medication and is common when an allergy specialist believes a patient might have outgrown their allergy. CRD, or Component Resolved Diagnostics, is an emerging tool that measures IgE antibodies using specific proteins within an allergen. The basophil activation test is the latest method, measuring a person’s basophils (a type of white blood cell) when exposed to food allergens.

While there are plenty of speculated and researched factors into the plausible causes for food allergies, there is not sufficient data across years that consider the global factors that contribute to a person’s health. There is a growing need for multicultural research and prevalence studies in non-Western countries to study the rising prevalence of food allergies. Climate change is another major contributor to the increasing prevalence of those impacted by food allergies worldwide, and scientists are still grappling with the increased speed with which people are being impacted by it.