You’ve seen it many times before: a patient presents with a possible food allergy. He points to a recent reaction—itchiness and vomiting—after eating a cookie containing Brazil nuts, his first encounter. Now he wants to know whether he’s sensitive to the nut, allergic, or if it is something else altogether.
Roughly 0.4%–0.5% of the U.S. population has a tree nut allergy (>1MM people).1 Even more people are allergic to other foods, including eggs, milk, and peanuts.1 Yet many people are merely sensitive to a particular food and may not be at risk for a serious reaction—this includes 78% of those sensitive to peanuts, for example.2
Standard immunoglobulin E (IgE) testing provides an objective assessment of sensitization and is the first step in discovering the likelihood of a systemic reaction. But while high levels of peanut IgE, for instance, can predict the likelihood of peanut sensitivity, they may not be predictive of reactions or allergic response.2
That’s because many food allergies are actually protein allergies, or reactions to components of foods. Testing for specific allergen proteins, then, can help you better diagnose allergies and sensitizations, and prepare personalized management plans for your patients.
Know the level of risk
In the case of a peanut sensitivity or allergy, 5 different proteins are associated with low, variable, and high risk of systemic reaction:
Allergen component testing can help you identify the protein your patient is sensitive to and better prepare a management plan. If your patient tests positive for an Ara h1, 2, or 3 protein sensitivity, the plan would include:
- Choosing peanut-free zones for safety
- Prescribing an epinephrine auto-injector
- Making family and colleagues aware of the allergy and having a plan in place
In the case of the patient with a possible Brazil nut allergy, a positive result for the protein Ber e1 allergy indicates cross-reactivity within the tree nut family9 and potentially life-threatening systemic reactions.10 The patient should also be made aware that this protein can be found not only in cookies but also in insect repellent and beauty products.11
Identify the cause with ImmunoCAP®
With the ImmunoCAP blood test from Quest Diagnostics, you can quantitatively measure specific IgE antibody blood levels and identify specific allergic sensitivities, including component testing for nuts, milk, and eggs:
- One simple blood draw
- Tests for 200+ food and environmental allergens
- Sensitivity comparable to that of skin prick testing—without the discomfort or risk of severe reaction
Allergen component testing allows you to assess risk for systemic reactions and cross-sensitivity, address patient anxiety with individualized management plans, and enable confidence in dietary and lifestyle choices. Learn more.
1. Boyce JA, Assa’ad A, Burks AW, et al. Guidelines for the diagnosis and management of food allergy in the United States. J Allergy Clin Immunol. 2010;126(6 0):S1-58.
2. Nicolaou N, Poorafshar M, Murray C, et al. Allergy or tolerance in children sensitized to peanut: prevalence and differentiation using component-resolved diagnostics. J Allergy Clin Immunol. 2010;125(1):191-197.
3. Asarnoj A, Nilsson C, Lidholm J, et al. Peanut component Ara h 8 sensitization and tolerance to peanut. J Allergy Clin Immunol. 2012;130(2):468-472.
4. Mittag D, Akkerdaas J, Ballmer-Weber BK, et al. Ara h 8, a Bet v 1-homologous allergen from peanut, is a major allergen in patients with combined birch pollen and peanut allergy. J Allergy Clin Immunol. 2004;114(6):1410-1417.
5. Lauer I, Dueringer N, Pokoj S, et al. The non-specific lipid transfer protein, Ara h 9, is an important allergen in peanut. Clin Exp Allergy. 2009;39(9):1427-1437.
6. Movérare R, Ahlstedt S, Bengtsson U, et al. Evaluation of IgE antibodies to recombinant peanut allergens in patients with reported reactions to peanut. Int Arch Allergy Immunol. 2011;156(3):282-290.
7. Peeters KA, Koppelman SJ, van Hoffen E, et al. Does skin prick test reactivity to purified allergens correlate with clinical severity of peanut allergy? Clin Exp Allergy. 2007;37(1):108-115.
8. Asarnoj A, Movérare R, Östblom E, et al. IgE to peanut allergen components: relation to peanut symptoms and pollen sensitization in 8-year-olds. Allergy. 2010;65(9):1189-1195.
9. Yman L. Botanical relations and immuno-logical cross-reactions in pollen allergy. 2nd ed. Pharmacia Diagnostics AB. Uppsala. Sweden. 1982: ISBN 91-970475-09.
10. Bartolome B, Mendez JD, Armentia A, Vallverdu A, Palacios R. Allergens from Brazil nut: immunochemical characterization. Allergol Immunopathol (Madr). 1997;25(3):135-144.
11. Thermo Scientific. Brazil nut. Available at: www.phadia.com/en/products/allergy-testing-products/immunocap-allergen-information/food-of-plant-origin/seeds–nuts/brazil-nut-/. Accessed April 26, 2018.