Why Early Exposure Is Transforming Food Allergy Treatment

For decades, the standard advice for managing food allergies has been simple but strict: complete avoidance. Parents of allergic children have lived with constant vigilance, carefully reading labels, grilling restaurant staff, and carrying epinephrine auto-injectors everywhere. But according to a comprehensive review published March 5 in Clinical & Experimental Allergy, this approach may be doing more harm than good, particularly for the youngest allergy sufferers.

The review, led by researchers at the University of British Columbia, challenges conventional wisdom by arguing that controlled exposure to allergens in preschool children—known as oral immunotherapy (OIT)—should be a primary treatment strategy rather than a last resort.

“This research highlights a critical shift in how we approach food allergies—moving from strict avoidance to controlled exposure in early childhood, which not only reduces the risk of severe reactions but also helps prevent long-term negative consequences of living with food allergies,” said corresponding author Lianne Soller, PhD, of the University of British Columbia.

The traditional “wait-and-see” approach, hoping children will naturally outgrow their allergies, may be missing a crucial window of opportunity. The review points to mounting evidence that a child’s immune system is more amenable to change—or “plastic”—during early childhood, making preschoolers ideal candidates for OIT.

While some children do naturally outgrow food allergies, recent data indicate this happens less frequently than previously thought. The review notes that natural resolution rates vary significantly by allergen: peanut (22-29%), tree nuts (9-14%), cow’s milk (41-92%), and egg (47-59%). For those who don’t outgrow their allergies, waiting until school age to offer treatment “means missing the window of opportunity where OIT is safest, and prolongs unnecessary dietary restrictions.”

Perhaps most compelling is the safety data. Contrary to fears that introducing allergens might trigger severe reactions, multiple studies show preschool OIT has an impressive safety record. In several large clinical trials, severe reactions were rare (0-3%), and epinephrine use was minimal (0-9%) during the buildup phase. These outcomes appear significantly better than similar treatments in older children and adults.

Dr. Edmond Chan, a co-author and Clinical Professor at the University of British Columbia, has been at the forefront of advocating for earlier intervention. His team’s research has shown that waiting to treat food allergies has consequences beyond just prolonging dietary restrictions.

“Even if the child’s allergy does not return, studies have demonstrated that perceived food allergy has similar impacts on quality of life than diagnosed food allergy,” the authors write. “Moreover, research has found that adolescents with food allergy self-report a lower quality of life compared with parent proxy report of quality of life in younger children.”

The timing of this paradigm shift coincides with alarming statistics about accidental exposures. One study found that 58% of children diagnosed with peanut allergy before age 4 had reactions over a five-year follow-up period, often more severe than their initial reaction. A nationwide American survey noted that 19% of families with food allergies reported at least one allergy-related emergency department visit in the previous year.

What makes preschoolers particularly suitable candidates for OIT? Several factors, according to the review:

First, allergic reactions, including anaphylaxis, are generally less severe in preschoolers. A French study of nearly 2,000 food-induced anaphylaxis episodes found only 3% occurred in infants under 12 months and 20% in preschoolers, compared to more than 75% in school-aged children.

Second, starting early appears to improve long-term adherence. A follow-up study of preschoolers who underwent OIT found that 93% were still consuming their allergen five years later. In contrast, studies of older patients show dramatically lower adherence rates, with as many as 25% completely stopping allergen consumption after treatment.

The authors suggest this difference may be partly due to taste aversion, which typically develops around ages 6-7 and can persist into adulthood. By starting OIT before this critical period, children may be more willing to continue consuming their allergen long-term.

The economic case for early intervention is also compelling. One study estimated cost savings of preschool peanut OIT reaching “$12.3 to $47 billion in the United States and $10.4 to $13.6 billion in Canada” over an 80-year span.

Dr. Timothy Vander Leek, another co-author and pediatric allergist, acknowledges that while the evidence is strong, questions remain. “Further work should be done to properly define protocols including maintenance doses, classify safety and tolerance measures, and carefully agree upon clinical endpoints,” the authors state.

The review also highlights research gaps, including the need for more data on the psychosocial impacts of OIT, particularly whether early intervention can reduce or prevent food allergy-associated anxiety.

Implementation challenges exist as well. With childhood food allergy estimated at 6%, the traditional approach to OIT—requiring baseline food challenges and multiple office visits—may be resource-intensive for healthcare systems. Access to specialist care and epinephrine remains limited in some regions.

Despite these hurdles, the authors conclude that “evidence continues to accumulate in favour of preschool OIT and suggests that OIT should play a key role in treatment of food allergies in preschoolers.”

For parents of food-allergic children, this review offers hope that the burden of constant vigilance might be lightened through early, proactive treatment rather than years of anxious avoidance. As the evidence mounts, many allergists are already shifting their practice to embrace this approach, potentially transforming the landscape of food allergy management for the next generation.