Food allergies affect approximately 8% of children and 10% of adults¹ in the United States. Of food-allergic adults, nearly half¹ report that at least one allergy developed during adulthood, not as an extension of a childhood diagnosis, but as a new sensitization to something they had eaten without incident for years. The clinical and operational implications of that for laboratories are real. Allergy testing volumes are not driven by a single patient demographic, and the information a diagnostic test result conveys may have different implications throughout life stages.

Allergy is not a static diagnosis. Both food and environmental allergens emerge and resolve throughout life, and laboratories that treat allergy diagnostics as a fixed workflow rather than a longitudinal one are likely leaving clinical value on the table.

Early life: What the atopic march tells labs about test selections

The atopic march describes how allergic disease typically unfolds from infancy. Atopic dermatitis comes first when the skin barrier is compromised, and allergen proteins can penetrate the dermis and trigger an IgE-mediated immune response before the child has encountered that food through the gut, the route normally associated with tolerance development. Because of this, sensitization may precede any oral exposure, and in many cases, a food allergy that might have been prevented with earlier intervention.

Current guidelines² support specific IgE testing for peanut in high-risk infants, especially those with severe eczema, as a tool for guiding early food introduction decisions. A high-sensitivity negative result in this context carries strong negative predictive value, giving clinicians confidence to introduce this potentially allergenic food at the recommended window of four to six months. Evidence from the LEAP trial³ and subsequent research supports early introduction as protective against food allergy development.

Test selection at this life stage calls for attention to timing. For example, clinicians may not test for environmental pollens in the first 12 to 18 months of life, since sensitization to seasonal allergens requires repeated seasonal exposure and results ordered too early will not reflect actual clinical status. However, indoor allergens like dust mites, pet dander, cockroach, and/or mold may be present in the home from birth, and sensitization to these allergens can develop early with constant exposure, an important factor for clinicians to be aware of.

Food allergy prevalence in children is approximately 8%, with milk, egg, wheat, and soy account for the most common early sensitizations. By age 12, approximately 64% of children⁴ with milk allergies have developed tolerance; for egg, roughly 68%⁵ by age 16; for soy, around 69%⁶ by age 10; and for wheat, about 65%⁷ by age 12. Peanut, tree nut, fish, and shellfish follow a different trajectory. Shellfish tolerance arises in only about 4% of cases⁸ over five to ten years. These patterns carry direct implications for how often a patient should be retested and which component tests make sense to order alongside whole allergen results.

The re-testing gap: Adolescents, adults, and stale diagnoses

Most of the tolerance development that will happen for milk, egg, soy, and wheat happens by early adolescence. That makes teenagers a critical re-testing cohort, and a largely underserved one. A patient diagnosed at age four who is now sixteen likely has a meaningfully different immune profile, and the clinical decision about whether they still need to carry an epinephrine auto-injector or avoid a food entirely should rely on current data, not a ten-year-old result.

Component-resolved diagnostics are particularly useful here. A positive whole allergen result at adolescence indicates sensitization, but it does not tell you whether the sensitization is driven by high-risk storage proteins or by cross-reactive components associated with milder or no clinical symptoms. This is especially important with peanut, since sensitization to Ara h 2, a storage protein stable to heat and digestion, is strongly associated with true clinical allergy and systemic reaction risk. Sensitization to Ara h 8, a PR-10 protein that cross-reacts with birch pollen, is more commonly associated with oral allergy syndrome or no reaction at all. Treating those two results identically may result in unnecessary food avoidance, unneeded anxiety, and unnecessary emergency preparedness for patients who may not need it.

With milk and egg, specific component markers predict whether tolerance is likely. Higher IgE to ovomucoid in egg and casein in milk have been associated⁹ with more persistent allergy and a lower probability of natural tolerance development. Knowing that before ordering a food challenge affects both the clinical decision and the downstream lab workflow.

For adults, there’s another consideration. A large population-based survey of more than 40,000 adults¹⁰ found that 19% believed they had a food allergy, but when symptom history was examined carefully, only about half, roughly 10%, had convincing IgE-mediated symptoms. The other 9% were carrying a self-reported or empirically assigned diagnosis with no diagnostic confirmation. For laboratories, this gap is not simply an operational concern, since clinicians ordering allergy diagnostic testing for these adults may be working from assumptions made in childhood or after a single reaction.

Without symptom history, a positive result in an adult who was never properly diagnosed as a child is not confirmation of allergy, it’s confirmation of sensitization. Clear reporting and active communication with ordering clinicians about the difference between sensitization and clinical allergy matter here as much as anywhere else in the lifespan.

How labs can support allergies across the lifespan

Modern food allergy care depends on integrating clinical history, specific IgE testing, and allergen component diagnostics. When used together, these tools help clinicians diagnose more accurately, identify when tolerance has developed, and make more informed decisions about oral food challenges and long-term management.

For laboratories, recognizing that allergic disease evolves across a patient's lifetime has real operational implications for allergen selection offerings, and how results are reported. A lifespan-based approach means aligning allergen selection, workflow design, and diagnostic technologies with the reality of how allergic disease develops and progresses across the lifespan.

References

1. Facts and Statistics. Food Allergy Research & Education. Accessed July 9, 2026. https://www.foodallergy.org/resources/facts-and-statistics. 
2. Togias A, Cooper SF, Acebal ML, et al. Addendum guidelines for the prevention of peanut allergy in the United States: Report of the National Institute of Allergy and Infectious Diseases-sponsored expert panel. J Allergy Clin Immunol. 2017;139(1):29-44. doi:10.1016/j.jaci.2016.10.010. Accessed from: https://www.niaid.nih.gov/sites/default/files/addendum-peanut-allergy-prevention-guidelines.pdf. 
3. Du Toit G, Roberts G, Sayre PH, et al. Randomized trial of peanut consumption in infants at risk for peanut allergy. N Engl J Med. 2015;372(9):803-813. doi:10.1056/NEJMoa1414850. 
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8. Will my child outgrow their food allergy? Anaphylaxis UK. Accessed July 9, 2026. https://www.anaphylaxis.org.uk/fact-sheet/outgrowing-allergy/.
9. Frischmeyer-Guerrerio PA, Rasooly M, Gu W, et al. IgE testing can predict food allergy status in patients with moderate to severe atopic dermatitis. Ann Allergy Asthma Immunol. 2019;122(4):393-400.e2. doi:10.1016/j.anai.2019.01.001.
10. Gupta RS, Warren CM, Smith BM, et al. Prevalence and severity of food allergies among US adults. JAMA Netw Open. 2019;2(1):e185630. doi:10.1001/jamanetworkopen.2018.5630.