Tree nut allergy

Tree nut allergy
Hazelnuts, a type of tree nut
SpecialtyImmunology Edit this on Wikidata
Differential diagnosisPeanut allergy

A tree nut allergy is a hypersensitivity to dietary substances from tree nuts and edible tree seeds causing an overreaction of the immune system which may lead to severe physical symptoms. Tree nuts include, but are not limited to, almonds, Brazil nuts, cashews, chestnuts, filberts/hazelnuts, macadamia nuts, pecans, pistachios,[1] shea nuts and walnuts.[note 1]

Management is by avoiding eating the causal nuts or foods that contain them among their ingredients, and a prompt treatment if there is an accidental ingestion.[2] Total avoidance is complicated because the declaration of the presence of trace amounts of allergens in foods is not mandatory in every country.[3][4][5]

Tree nut allergies are distinct from peanut allergy, as peanuts are legumes, whereas a tree nut is a hard-shelled nut.

Signs and symptoms

The severity of the allergy varies from person to person, and exposure can increase sensitization. For those with a milder form of the allergy, a reaction which makes the throat feel like cotton may occur. Subjects allergic to tree nut can experience asthma, skin rashes, itchy throat, swollen eyes. The most severe reaction can lead to anaphylaxis.

The raw nut protein usually causes a more severe reaction than the oil, and extra roasting or processing can reduce the allergic reaction.

This allergy tends to be lifelong; studies have shown that only about 9% of children outgrow their tree nut allergy.[6]

Cause

People with tree nut allergy are seldom allergic to just one type of nut,[7][8] and are therefore usually advised to avoid all tree nuts, even though an individual may not be allergic to the nuts of all species of trees.

Someone allergic to walnuts or pecans may not have an allergy to cashews or pistachios, because the two groups are only distantly related and do not necessarily share related allergenic proteins.[9]

Diagnosis

An allergy test or food challenge may be performed at an allergy clinic to determine the exact allergens.

A tree nut allergy can be life threatening. If you believe that you may be having allergic reactions to any kind of tree nut, get tested by an allergist immediately.[10] Tree nut allergies can be genetic and passed down.[11] The test to get to determine if you have an allergy are skin-prick tests as well as blood tests. What they’re looking for is the presence of a specific allergen named immunoglobulin E which is an antibody that attaches itself to allergens. This triggers the chemicals that flow through your body and causes the symptoms.[10]

If the test results are inconclusive, there is also an oral food challenge. This test consists of feeding the patient tiny amounts of the food that they believe is causing their allergy reactions. This is done under direct supervision of the allergist.[10]

Prevention

Prevention involves an exclusion diet and vigilant avoidance of foods that may be contaminated with tree nuts, nut particles, or oils extracted from nuts. In the United States, the federal Food Allergen Labeling and Consumer Protection Act (FALCPA) requires that any packaged food product that contains tree nuts as an ingredient must list the specific tree nut on the label.[6] Foods that almost always contain tree nuts include pesto, marzipan, Nutella, baklava, pralines, nougat, gianduja, and turrón. Other common foods that may contain tree nuts include cereals, crackers, cookies, baked goods, candy, chocolates, energy/granola bars, flavored coffee, frozen desserts, marinades, barbecue sauces, and some cold cuts, such as mortadella. Tree nut oils (especially shea nut) are also sometimes used in lotions and soaps. Asian and African restaurants, ice cream parlors, and bakeries are considered high-risk for people with tree nut allergy due to the common use of nuts and the possibility of cross contamination.

Cross-reactivity

People with clinically confirmed tree nut allergy to one type of tree nut may have cross-reactivity to other tree nut species and also to peanuts, which are not nuts but rather part of the legume family.[12][13] The cause is similarity in protein structures. Identifiable allergenic proteins are grouped into families: cupins, prolamins, profilin and others. Tree nuts have proteins in these families, as do peanuts and other legumes.[12] Reviews of human trials report that for a confirmed tree nut allergy, up to one third of people will react to more than one type of tree nut. The cross reactivity among almond, walnut, pecan, hazelnut and Brazil nut is stronger than cross reactivity of these toward cashew or pistachio.[13]

Treatment

Strict dietary avoidance of the causal nut(s) remains the mainstay of treatment for nut-allergic individuals. If the food is accidentally ingested and a systemic reaction (anaphylaxis) occurs, then epinephrine should be used. People with potential anaphylaxis are recommended to carry auto-injectors at all times.[2] Less severe reaction may be dealt with by taking an antihistamine tablet.

Total avoidance is complicated because the declaration of the presence of trace amounts of allergens in foods is not mandatory (see regulation of labelling).

Society and culture

Whether food allergy prevalence is increasing or not, food allergy awareness has increased, with impacts on the quality of life for children, their parents and their immediate caregivers.[14][15][16][17] In the United States, the Food Allergen Labeling and Consumer Protection Act of 2004 causes people to be reminded of allergy problems every time they handle a food package, and restaurants have added allergen warnings to menus. The Culinary Institute of America, a premier school for chef training, has courses in allergen-free cooking and a separate teaching kitchen.[18] School systems have protocols about what foods can be brought into the school. Despite all these precautions, people with serious allergies are aware that accidental exposure can easily occur at other peoples' houses, at school or in restaurants.[19] Food fear has a significant impact on quality of life.[16][17] Finally, for children with allergies, their quality of life is also affected by actions of their peers. There is an increased occurrence of bullying, which can include threats or acts of deliberately being touched with foods they need to avoid, also having their allergen-free food deliberately contaminated.[20]

Regulation of labelling

An example of a list of allergens in a food item

In response to the risk that certain foods pose to those with food allergies, some countries have responded by instituting labeling laws that require food products to clearly inform consumers if their products contain major allergens or byproducts of major allergens among the ingredients intentionally added to foods. Nevertheless, there are no labeling laws to mandatory declare the presence of trace amounts in the final product as a consequence of cross-contamination, except in Brazil.[5][21][22][23][24][25][4][3]

Ingredients intentionally added

In the United States, the Food Allergen Labeling and Consumer Protection Act of 2004 (FALCPA) requires companies to disclose on the label whether a packaged food product contains any of these eight major food allergens, added intentionally: cow's milk, peanuts, eggs, shellfish, fish, tree nuts, soy and wheat.[21] This list originated in 1999 from the World Health Organisation Codex Alimentarius Commission.[4] To meet FALCPA labeling requirements, if an ingredient is derived from one of the required-label allergens, then it must either have its "food sourced name" in parentheses, for example "Casein (milk)," or as an alternative, there must be a statement separate but adjacent to the ingredients list: "Contains milk" (and any other of the allergens with mandatory labeling).[21][23] The European Union requires listing for those eight major allergens plus molluscs, celery, mustard, lupin, sesame and sulfites.[22]

FALCPA applies to packaged foods regulated by the FDA, which does not include poultry, most meats, certain egg products, and most alcoholic beverages.[3] However, some meat, poultry, and egg processed products may contain allergenic ingredients. These products are regulated by the Food Safety and Inspection Service (FSIS), which requires that any ingredient be declared in the labeling only by its common or usual name. Neither the identification of the source of a specific ingredient in a parenthetical statement nor the use of statements to alert for the presence of specific ingredients, like "Contains: milk", are mandatory according to FSIS.[24][25] FALCPA also does not apply to food prepared in restaurants.[26][27] The EU Food Information for Consumers Regulation 1169/2011 – requires food businesses to provide allergy information on food sold unpackaged, for example, in catering outlets, deli counters, bakeries and sandwich bars.[28]

In the United States, there is no federal mandate to address the presence of allergens in drug products. FALCPA does not apply to medicines nor to cosmetics.[29]

Trace amounts as a result of cross-contamination

The value of allergen labeling other than for intentional ingredients is controversial. This concerns labeling for ingredients present unintentionally as a consequence of cross-contact or cross-contamination at any point along the food chain (during raw material transportation, storage or handling, due to shared equipment for processing and packaging, etc.).[4][3] Experts in this field propose that if allergen labeling is to be useful to consumers, and healthcare professionals who advise and treat those consumers, ideally there should be agreement on which foods require labeling, threshold quantities below which labeling may be of no purpose, and validation of allergen detection methods to test and potentially recall foods that were deliberately or inadvertently contaminated.[30][31]

Labeling regulations have been modified to provide for mandatory labeling of ingredients plus voluntary labeling, termed precautionary allergen labeling (PAL), also known as “may contain” statements, for possible, inadvertent, trace amount, cross-contamination during production.[4][32] PAL labeling can be confusing to consumers, especially as there can be many variations on the wording of the warning.[32][33] As of 2014 PAL is regulated only in Switzerland, Japan, Argentina, and South Africa. Argentina decided to prohibit precautionary allergen labeling since 2010, and instead puts the onus on the manufacturer to control the manufacturing process and label only those allergenic ingredients known to be in the products. South Africa does not permit the use of PAL, except when manufacturers demonstrate the potential presence of allergen due to cross-contamination through a documented risk assessment and despite adherence to Good Manufacturing Practice.[4] In Australia and New Zealand there is a recommendation that PAL be replaced by guidance from VITAL 2.0 (Vital Incidental Trace Allergen Labeling). A review identified "the eliciting dose for an allergic reaction in 1% of the population" as ED01. This threshold reference dose for foods (such as cow's milk, egg, peanut and other proteins) will provide food manufacturers with guidance for developing precautionary labeling and give consumers a better idea of might be accidentally in a food product beyond "may contain."[34][35] VITAL 2.0 was developed by the Allergen Bureau, a food industry sponsored, non-government organization.[36] The European Union has initiated a process to create labeling regulations for unintentional contamination but is not expected to publish such before 2024.[37]

In Brazil since April 2016, the declaration of the possibility of cross-contamination is mandatory when the product does not intentionally add any allergenic food or its derivatives, but the Good Manufacturing Practices and allergen control measures adopted are not sufficient to prevent the presence of accidental trace amounts. These allergens include wheat, rye, barley, oats and their hybrids, crustaceans, eggs, fish, peanuts, soybean, milk of all species of mammalians, almonds, hazelnuts, cashew nuts, Brazil nuts, macadamia nuts, walnuts, pecan nuts, pistaches, pine nuts, and chestnuts.[5]

Research

Immunotherapy treatments are being developed for tree nut allergy, including oral immunotherapy, sublingual immunotherapy, and epicutaneous immunotherapy.[2]

See also

Notes

  1. ↑ Many seeds are commonly referred to as "nuts" even though botanists use the term more restrictively to refer to those that come from indehiscent fruits. See the article about nuts for more information.

References

  1. ↑ "Tree nut allergy". Food Allergy Research and Education.
  2. 1 2 3 Weinberger T, Sicherer S (2018). "Current perspectives on tree nut allergy: a review". Journal of Asthma and Allergy (Review). 11: 41–51. doi:10.2147/JAA.S141636. PMC 5875412. PMID 29618933.
  3. 1 2 3 4 FDA (18 December 2017). "Food Allergies: What You Need to Know". Food and Drug Administration. Retrieved 12 January 2018.
  4. 1 2 3 4 5 6 Allen KJ, Turner PJ, Pawankar R, Taylor S, Sicherer S, Lack G, Rosario N, Ebisawa M, Wong G, Mills EN, Beyer K, Fiocchi A, Sampson HA (2014). "Precautionary labelling of foods for allergen content: are we ready for a global framework?". World Allergy Organization Journal. 7 (1): 1–14. doi:10.1186/1939-4551-7-10. PMC 4005619. PMID 24791183.
  5. 1 2 3 "Agência Nacional de Vigilância Sanitária Guia sobre Programa de Controle de Alergênicos" (in Portuguese). Agência Nacional de Vigilância Sanitária (ANVISA). 2016. Retrieved 7 April 2018.
  6. 1 2 National Institutes of Health, NIAID Allergy Statistics. "Archived copy". Archived from the original on April 6, 2010. Retrieved December 18, 2011.{{cite web}}: CS1 maint: archived copy as title (link)
  7. ↑ Goetz, DW (July 2005). "Cross-reactivity among edible nuts: double immunodiffusion, crossed immunoelectrophoresis, and human specific igE serologic surveys. (Abstract)". Annals of Allergy, Asthma & Immunology. 95 (1): 45–52. doi:10.1016/S1081-1206(10)61187-8. PMID 16095141.
  8. ↑ MD, Scott H. Sicherer, ed. (2014). Food allergy : practical diagnosis and management (1 ed.). Boca Raton: CRC Press. p. 29. ISBN 9781466512689.
  9. ↑ Goetz, David W.; Whisman, Bonnie A.; Goetz, Andrew D. (July 1, 2005). "Cross-reactivity among edible nuts: double immunodiffusion, crossed immunoelectrophoresis, and human specific IgE serologic surveys". Annals of Allergy, Asthma & Immunology. 95 (1): 45–52. doi:10.1016/S1081-1206(10)61187-8. PMID 16095141.
  10. 1 2 3 "Tree Nut".
  11. ↑ "All About Allergies (For Parents) - Nemours Kidshealth".
  12. 1 2 Bublin M, Breiteneder H (2014). "Developing therapies for peanut allergy". International Archives of Allergy and Immunology. 165 (3): 179–194. doi:10.1159/000369340. PMC 5548240. PMID 25531161.
  13. 1 2 Lomas JM, Järvinen KM (2015). "Managing nut-induced anaphylaxis: challenges and solutions". Journal of Asthma and Allergy. 8: 115–123. doi:10.2147/JAA.S89121. PMC 4631427. PMID 26604803.
  14. ↑ Ravid NL, Annunziato RA, Ambrose MA, Chuang K, Mullarkey C, Sicherer SH, Shemesh E, Cox AL (2015). "Mental health and quality-of-life concerns related to the burden of food allergy". Psychiatric Clinics of North America. 38 (1): 77–89. doi:10.1016/j.psc.2014.11.004. PMID 25725570.
  15. ↑ Morou Z, Tatsioni A, Dimoliatis ID, Papadopoulos NG (2014). "Health-related quality of life in children with food allergy and their parents: a systematic review of the literature". Journal of Investigational Allergology & Clinical Immunology. 24 (6): 382–95. PMID 25668890.
  16. 1 2 Lange L (2014). "Quality of life in the setting of anaphylaxis and food allergy". Allergo Journal International. 23 (7): 252–260. doi:10.1007/s40629-014-0029-x. PMC 4479473. PMID 26120535.
  17. 1 2 van der Velde JL, Dubois AE, Flokstra-de Blok BM (2013). "Food allergy and quality of life: what have we learned?". Current Allergy and Asthma Reports. 13 (6): 651–61. doi:10.1007/s11882-013-0391-7. PMID 24122150. S2CID 326837.
  18. ↑ Culinary Institute of America Allergen-free oasis comes to the CIA (2017)
  19. ↑ Shah E, Pongracic J (2008). "Food-induced anaphylaxis: who, what, why, and where?". Pediatric Annals. 37 (8): 536–41. doi:10.3928/00904481-20080801-06. PMID 18751571.
  20. ↑ Fong AT, Katelaris CH, Wainstein B (2017). "Bullying and quality of life in children and adolescents with food allergy". Journal of Paediatrics and Child Health. 53 (7): 630–635. doi:10.1111/jpc.13570. PMID 28608485. S2CID 9719096.
  21. 1 2 3 "Food Allergen Labeling and Consumer Protection Act of 2004". FDA. August 2, 2004. Archived from the original on 2011-02-02.
  22. 1 2 "Food allergen labelling and information requirements under the EU Food Information for Consumers Regulation No. 1169/2011: Technical Guidance" (April 2015).
  23. 1 2 FDA (14 December 2017). "Have Food Allergies? Read the Label". Food and Drug Administration. Retrieved 14 January 2018.
  24. 1 2 "Food Ingredients of Public Health Concern" (PDF). United States Department of Agriculture. Food Safety and Inspection Service. 7 March 2017. Retrieved 16 February 2018.
  25. 1 2 "Allergies and Food Safety". United States Department of Agriculture. Food Safety and Inspection Service. 1 December 2016. Retrieved 16 February 2018.
  26. ↑ Roses JB (2011). "Food allergen law and the Food Allergen Labeling and Consumer Protection Act of 2004: falling short of true protection for food allergy sufferers". Food and Drug Law Journal. 66 (2): 225–42, ii. PMID 24505841.
  27. ↑ FDA (18 July 2006). "Food Allergen Labeling And Consumer Protection Act of 2004 Questions and Answers". Food and Drug Administration. Retrieved 12 March 2018.
  28. ↑ "Allergy and intolerance: guidance for businesses". Archived from the original on 2014-12-08. Retrieved 2014-12-12.
  29. ↑ Shah AV, Serajuddin AT, Mangione RA (2017). "Making All Medications Gluten Free". Journal of Pharmaceutical Sciences. 107 (5): 1263–1268. doi:10.1016/j.xphs.2017.12.021. PMID 29287928.
  30. ↑ Mills EN, Valovirta E, Madsen C, Taylor SL, Vieths S, Anklam E, Baumgartner S, Koch P, Crevel RW, Frewer L (2004). "Information provision for allergic consumers--where are we going with food allergen labelling?". Allergy. 59 (12): 1262–1268. doi:10.1111/j.1398-9995.2004.00720.x. PMID 15507093. S2CID 40395908.
  31. ↑ Taylor SL, Baumert JL (2015). "Worldwide food allergy labeling and detection of allergens in processed foods". Food Allergy: Molecular Basis and Clinical Practice. Chemical Immunology and Allergy. Vol. 101. pp. 227–234. doi:10.1159/000373910. ISBN 978-3-318-02340-4. PMID 26022883.
  32. 1 2 DunnGalvin A, Chan CH, et al. (2015). "Precautionary allergen labelling: perspectives from key stakeholder groups". Allergy. 70 (9): 1039–1051. doi:10.1111/all.12614. PMID 25808296. S2CID 18362869.
  33. ↑ Zurzolo GA, de Courten M, Koplin J, Mathai ML, Allen KJ (2016). "Is advising food allergic patients to avoid food with precautionary allergen labelling out of date?". Current Opinion in Allergy & Clinical Immunology. 16 (3): 272–277. doi:10.1097/ACI.0000000000000262. PMID 26981748. S2CID 21326926.
  34. ↑ Allen KJ, Remington BC, Baumert JL, Crevel RW, Houben GF, Brooke-Taylor S, Kruizinga AG, Taylor SL (2014). "Allergen reference doses for precautionary labeling (VITAL 2.0): clinical implications". Journal of Allergy and Clinical Immunology. 133 (1): 156–164. doi:10.1016/j.jaci.2013.06.042. PMID 23987796.
  35. ↑ Taylor SL, Baumert JL, Kruizinga AG, Remington BC, Crevel RW, Brooke-Taylor S, Allen KJ, Houben G (2014). "Establishment of Reference Doses for residues of allergenic foods: report of the VITAL Expert Panel". Food and Chemical Toxicology. 63: 9–17. doi:10.1016/j.fct.2013.10.032. PMID 24184597.
  36. ↑ The VITAL Program Allergen Bureau, Australia and New Zealand.
  37. ↑ Popping B, Diaz-Amigo C (2018). "European Regulations for Labeling Requirements for Food Allergens and Substances Causing Intolerances: History and Future". Journal of AOAC International. 101 (1): 2–7. doi:10.5740/jaoacint.17-0381. PMID 29202901.
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