View source for Tree nut allergy

{{Infobox medical condition (new)
| name            = Tree nut allergy
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| caption         = [[Hazelnut]]s, a type of tree nut
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| differential    = [[Peanut allergy]]
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A '''tree nut allergy''' is a [[Type I hypersensitivity|hypersensitivity]] to [[diet (nutrition)|dietary]] substances from tree [[Nut (fruit)|nut]]s and edible tree [[seed]]s, causing an overreaction of the immune system, which may lead to severe physical symptoms. Tree nuts include [[almond]]s, [[Brazil nut]]s, [[cashew]]s, [[chestnut]]s, [[hazelnut|filberts/hazelnuts]], [[macadamia nut]]s, [[pecan]]s, [[pistachio]]s,<ref name=autogenerated1>{{cite web |agency= Food Allergy Research and Education |title= Tree nut allergy |url= http://www.foodallergy.org/allergens/tree-nut-allergy }}</ref> [[shea nut]]s, and [[walnut]]s.<ref group=note>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 [[Nut (fruit)|nuts]] for more information.</ref>

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.<ref name="WeinbergerSicherer2018" /> Total avoidance is complicated because the declaration of the presence of trace amounts of allergens in foods is not mandatory in every country.<ref name=FDAallergies2017 /><ref name=Allen2014 /><ref name="ANVISA2016" />

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

==Signs and symptoms==
[[File:Signs and symptoms of anaphylaxis.png|350px|right|Signs and symptoms of anaphylaxis]]
Food allergies in general usually have an onset of symptoms in the range of minutes to hours for an [[immunoglobulin E]] (IgE)-mediated response, which may include [[anaphylaxis]].<ref name="Muraro2014">{{cite journal |vauthors=Muraro A, Roberts G, Worm M, Bilò MB, Brockow K, Fernández Rivas M, Santos AF, Zolkipli ZQ, Bellou A, Beyer K, Bindslev-Jensen C, Cardona V, Clark AT, Demoly P, Dubois AE, DunnGalvin A, Eigenmann P, Halken S, Harada L, Lack G, Jutel M, Niggemann B, Ruëff F, Timmermans F, Vlieg-Boerstra BJ, Werfel T, Dhami S, Panesar S, Akdis CA, Sheikh A |display-authors=5 |title=Anaphylaxis: guidelines from the European Academy of Allergy and Clinical Immunology |journal=Allergy |volume=69 |issue=8 |pages=1026–45 |date=August 2014 |pmid=24909803 |doi=10.1111/all.12437 |s2cid=11054771 |url=}}</ref> Symptoms may include rash, [[hives]], itching of mouth, lips, tongue, throat, eyes, skin, or other areas, swelling of lips, tongue, eyelids, or the whole face, difficulty swallowing, runny or congested nose, hoarse voice, wheezing, shortness of breath, diarrhea, abdominal pain, lightheadedness, fainting, nausea, or vomiting.<ref name=medlineplus>{{MedlinePlusEncyclopedia|000817|Food allergy}}</ref> Non-IgE-mediated responses occur hours to days after consuming the allergenic food, and are not as severe as IgE-mediated symptoms. Symptoms of allergies vary from person to person and incident to incident.<ref name=medlineplus/>

Potentially life-threatening, the anaphylactic onset of an allergic reaction is characterized by respiratory distress, as indicated by wheezing, breathing difficulty, and [[cyanosis]], and also circulatory impairment that can include a weak pulse, pale skin, and fainting. This can occur when IgE antibodies are released<ref>{{Cite journal|last1=Reber|first1=LL|last2=Hernandez|first2=JD|last3=Galli|first3=SJ|date=August 2017|title=The pathophysiology of anaphylaxis|journal=The Journal of Allergy and Clinical Immunology|volume=140|issue=2|pages=335–348|doi=10.1016/j.jaci.2017.06.003|issn=0091-6749|pmc=5657389|pmid=28780941}}</ref> and areas of the body not in direct contact with the food allergen show severe symptoms.<ref name=medlineplus/><ref name="Muraro2014"/><ref name="Sicherer2014">{{Cite journal | vauthors=Sicherer SH, Sampson HA | title = Food allergy: Epidemiology, pathogenesis, diagnosis, and treatment |journal=J Allergy Clin Immunol |volume=133 |issue=2 | pages = 291–307 |date=February 2014 | doi = 10.1016/j.jaci.2013.11.020 | pmid=24388012}}</ref> Untreated, the overall response can lead to [[vasodilation]], which can be a low blood pressure situation called [[anaphylactic shock]].<ref name=Sicherer2014/>

Consumption of raw nuts usually causes a more severe reaction than roasted nuts or food-grade nut oils, as processing can reduce the integrity of the allergic proteins.<ref>{{Cite journal |last1=Zhang |first1=Tong |last2=Shi |first2=Yunfeng |last3=Zhao |first3=Yanqing |last4=Tang |first4=Guowei |last5=Niu |first5=Bing |last6=Chen |first6=Qin |date=September 2018 |title=Boiling and roasting treatment affecting the peanut allergenicity |journal=Annals of Translational Medicine |volume=6 |issue=18 |pages=357 |doi=10.21037/atm.2018.05.08 |pmc=6186550 |pmid=30370284 |doi-access=free }}</ref>

==Causes==
{{Expand section|date=November 2024}}
Tree nut allergies are caused by an irregular immune system reaction to biological proteins found across many tree nuts which the immune system's Immunoglobulin E treats as harmful invaders.<ref>https://www.foodallergy.org/living-food-allergies/food-allergy-essentials/common-allergens/tree-nut</ref> Proteins responsible for tree nut allergies include [[Plant lipid transfer proteins|lipid transfer proteins]], [[profilin]], [[Globulin]]s, [[Albumin]]s, and [[PR-10 (plant protein)|PR-10]].<ref>{{cite journal | pmc=9330593 | date=2022 | last1=Führer | first1=S. | last2=Unterhauser | first2=J. | last3=Zeindl | first3=R. | last4=Eidelpes | first4=R. | last5=Fernández-Quintero | first5=M. L. | last6=Liedl | first6=K. R. | last7=Tollinger | first7=M. | title=The Structural Flexibility of PR-10 Food Allergens | journal=International Journal of Molecular Sciences | volume=23 | issue=15 | page=8252 | doi=10.3390/ijms23158252 | doi-access=free | pmid=35897827 }}</ref><ref>{{cite journal | pmc=5875412 | date=2018 | last1=Weinberger | first1=T. | last2=Sicherer | first2=S. | title=Current perspectives on tree nut allergy: A review | journal=Journal of Asthma and Allergy | volume=11 | pages=41–51 | doi=10.2147/JAA.S141636 | doi-access=free | pmid=29618933 }}</ref>

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

Since a tree nut allergy can be life-threatening, people who suspect they are having allergic reactions to any kind of tree nut should be tested by an allergist immediately.<ref name="acaai.org">{{Cite web|url=https://acaai.org/allergies/allergic-conditions/food/tree-nut/|title=Tree Nut &#124; Causes, Symptoms & Treatment|website=ACAAI Public Website}}</ref> Tree nut allergies can be genetic and passed down.<ref>{{Cite web|url=https://kidshealth.org/en/parents/allergy.html|title = All About Allergies (For Parents) - Nemours Kidshealth}}</ref> Skin-prick tests and blood tests may be used to determine if an allergy is present. Tests can reveal the presence of [[immunoglobulin E]] (IgE), an antibody that responds to allergens and triggers the release of chemicals which cause the symptoms.<ref name="acaai.org"/>

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 allergic reactions. This is done under the direct supervision of the allergist.<ref name="acaai.org"/>

==Prevention==
Prevention involves an exclusion [[Dieting|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.<ref name=autogenerated2 />  Foods that almost always contain tree nuts include [[pesto]], [[marzipan]], [[Nutella]], [[baklava]], [[Praline (nut confection)|pralines]], [[nougat]], [[gianduja (chocolate)|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]].<ref>{{Cite journal |last1=Furlong |first1=Terence J. |last2=DeSimonea |first2=Jennifer |last3=Sicherer |first3=Scott H. |date=November 2001 |title=Peanut and tree nut allergic reactions in restaurants and other food establishments |journal=Journal of Allergy and Clinical Immunology |volume=108 |issue=5 |pages=867–870 |doi=10.1067/mai.2001.119157 |pmid=11692117 |issn=0091-6749|doi-access=free }}</ref>

===Cross-reactivity===
{{gallery|mode=packed
|Almonds - in shell, shell cracked open, shelled, blanched.jpg|Almonds: shell cracked open, whole shell, shelled, blanched
|Pecan halves with centimeter scale.jpg|Pecan halves removed from shell
|Walnuts - whole and open with halved kernel.jpg|Walnuts: whole shell, shell cracked open, shelled piece 
|BrazilNut1.JPG|Brazil nuts in shells
|CashewSnack.jpg|Cashew nuts shelled and roasted
|title=Gallery of tree nuts}}
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.<ref name=Bublin>{{cite journal |vauthors=Bublin M, Breiteneder H |title=Developing therapies for peanut allergy |journal=International Archives of Allergy and Immunology|volume=165 |issue=3 |pages=179–194 |year=2014 |pmid=25531161 |pmc=5548240 |doi=10.1159/000369340 }}</ref><ref name=Lomas>{{cite journal |vauthors=Lomas JM, Järvinen KM |title=Managing nut-induced anaphylaxis: challenges and solutions |journal=Journal of Asthma and Allergy|volume=8 |pages=115–123 |year=2015 |pmid=26604803 |pmc=4631427 |doi=10.2147/JAA.S89121 |doi-access=free }}</ref> The cause is similarity in protein structures. Identifiable allergenic proteins are grouped into families: cupins, prolamins, profilins, and others. Tree nuts have proteins in these families, as do peanuts and other legumes.<ref name=Bublin /> 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 the cross reactivity of these toward cashew or pistachio.<ref name=Lomas />

People with tree nut allergy are seldom allergic to just one type of nut,<ref>{{cite journal |last1=Goetz |first1=DW |title= Cross-reactivity among edible nuts: double immunodiffusion, crossed immunoelectrophoresis, and human specific IgE serologic surveys. (Abstract)|date=July 2005 |pmid= 16095141 |doi= 10.1016/S1081-1206(10)61187-8 |volume=95 |issue=1 |journal= Annals of Allergy, Asthma & Immunology |pages=45–52}}</ref><ref>{{cite book |editor-last1=MD |editor-first1=Scott H. Sicherer |title=Food allergy: practical diagnosis and management |date=2014 |publisher=CRC Press |location= Boca Raton |isbn= 9781466512689 |pages=29 |edition=1 }}</ref> 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.<ref>{{cite journal |last1=Goetz |first1=David W. |last2=Whisman |first2=Bonnie A. |last3=Goetz |first3=Andrew D. |title=Cross-reactivity among edible nuts: double immunodiffusion, crossed immunoelectrophoresis, and human specific IgE serologic surveys |journal=Annals of Allergy, Asthma & Immunology|date=July 1, 2005 |volume=95 |issue=1 |pages=45–52 |doi=10.1016/S1081-1206(10)61187-8|pmid=16095141 }}</ref>

==Prognosis==
This allergy tends to be lifelong; studies have shown that only about 9% of children outgrow their tree nut allergy.<ref name=autogenerated2>National Institutes of Health, NIAID Allergy Statistics. {{cite web |url=http://www3.niaid.nih.gov/topics/foodAllergy/understanding/quickFacts.htm |title=Food Allergy Quick Facts |access-date= December 18, 2011 |url-status=dead |archive-url= https://web.archive.org/web/20100406085101/http://www3.niaid.nih.gov/topics/foodAllergy/understanding/quickFacts.htm |archive-date= April 6, 2010 }}</ref>

==Treatment==
[[File:epipen.jpg|thumb|Epinephrine autoinjectors are portable single-dose epinephrine-dispensing devices used to treat anaphylaxis.]]
Strict dietary avoidance of the causal nut(s) remains the mainstay of treatment for nut-allergic individuals.<ref name="WeinbergerSicherer2018">{{cite journal| vauthors=Weinberger T, Sicherer S| title=Current perspectives on tree nut allergy: a review. | journal=Journal of Asthma and Allergy| year= 2018 | volume= 11 | pages= 41–51 | pmid=29618933 | doi=10.2147/JAA.S141636 | pmc=5875412 | type=Review | doi-access=free }}</ref> Treatment for accidental ingestion of tree nut products by allergic individuals varies depending on the sensitivity of the person. An [[antihistamine]] such as [[diphenhydramine]] may be prescribed. Sometimes [[prednisone]] will be prescribed to prevent a possible late-phase [[Type I hypersensitivity]] reaction.<ref>{{cite journal | author = Tang AW | title = A practical guide to anaphylaxis | journal = Am Fam Physician | date = 2003 | volume = 68 | issue = 7 | pages = 1325–1332| pmid =14567487}}</ref> Severe allergic reactions (anaphalaxis) may require treatment with an [[epinephrine pen]], which is an injection device designed to be used by a non-healthcare professional when emergency treatment is warranted.<ref name=EAACI2014>{{cite journal|author=The EAACI Food Allergy and Anaphylaxis Guidelines Group|s2cid=11054771|title=Anaphylaxis: guidelines from the European Academy of Allergy and Clinical Immunology.|journal=Allergy|date=August 2014|volume=69|issue=8|pages=1026–45|pmid=24909803|doi=10.1111/all.12437}}</ref>

==Regulation==
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.<ref name=Ravid2015>{{cite journal |vauthors=Ravid NL, Annunziato RA, Ambrose MA, Chuang K, Mullarkey C, Sicherer SH, Shemesh E, Cox AL |title=Mental health and quality-of-life concerns related to the burden of food allergy |journal=Psychiatric Clinics of North America|volume=38 |issue=1 |pages=77–89 |year=2015 |pmid=25725570 |doi=10.1016/j.psc.2014.11.004 }}</ref><ref name=Morou2014>{{cite journal |vauthors=Morou Z, Tatsioni A, Dimoliatis ID, Papadopoulos NG |title=Health-related quality of life in children with food allergy and their parents: a systematic review of the literature |journal=Journal of Investigational Allergology & Clinical Immunology|volume=24 |issue=6 |pages=382–95 |year=2014 |pmid=25668890 }}</ref><ref name=Lange2014>{{cite journal |vauthors=Lange L |title=Quality of life in the setting of anaphylaxis and food allergy |journal=Allergo Journal International|volume=23 |issue=7 |pages=252–260 |year=2014 |pmid=26120535 |pmc=4479473 |doi=10.1007/s40629-014-0029-x }}</ref><ref name=Velde2013>{{cite journal |vauthors=van der Velde JL, Dubois AE, Flokstra-de Blok BM |title=Food allergy and quality of life: what have we learned? |journal=Current Allergy and Asthma Reports|volume=13 |issue=6 |pages=651–61 |year=2013 |pmid=24122150 |doi=10.1007/s11882-013-0391-7 |s2cid=326837 }}</ref> In the United States, the [[Food Allergen Labeling and Consumer Protection Act]] enacted August 2004, effective January 1, 2006, causes people to be reminded of allergy problems every time they handle a food package, and restaurants have added allergen warnings to menus.<ref name=FDA2004 /> [[The Culinary Institute of America]], a premier school for chef training, has courses in allergen-free cooking and a separate teaching kitchen.<ref>[https://www.ciachef.edu/cia-allergen-free-dining-oasis-release/ Culinary Institute of America] Allergen-free oasis comes to the CIA (2017)</ref> 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.<ref name=Shah2008>{{cite journal |vauthors=Shah E, Pongracic J |title=Food-induced anaphylaxis: who, what, why, and where? |journal=Pediatric Annals|volume=37 |issue=8 |pages=536–41 |year=2008 |pmid=18751571 |doi= 10.3928/00904481-20080801-06}}</ref> 

===Regulation of labeling===
[[File:US Allergen Information Example.jpg|thumb|upright=1.3|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 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 mandatorily declare the presence of trace amounts in the final product as a consequence of cross-contamination, except in Brazil.<ref name="ANVISA2016">{{cite web|title=Agência Nacional de Vigilância Sanitária Guia sobre Programa de Controle de Alergênicos|url=https://www.saude.rj.gov.br/comum/code/MostrarArquivo.php?C=MzIxOQ%2C%2C|publisher=Agência Nacional de Vigilância Sanitária (ANVISA)|date=2016|access-date=7 April 2018|language=pt}}</ref>

<ref name=FDA2004>{{cite web |url=https://www.fda.gov/media/77570/download |archive-url=https://web.archive.org/web/20191214032633/https://www.fda.gov/media/77570/download |url-status=dead |archive-date=December 14, 2019 |publisher=US Food and Drug Administration |title=Food Allergen Labeling and Consumer Protection Act of 2004 |date=2 August 2004|access-date=7 March 2022}}</ref><ref name=EU2015>[https://www.food.gov.uk/sites/default/files/food-allergen-labelling-technical-guidance.pdf "Food allergen labelling and information requirements under the EU Food Information for Consumers Regulation No. 1169/2011: Technical Guidance"] {{Webarchive|url=https://web.archive.org/web/20170707062644/https://www.food.gov.uk/sites/default/files/food-allergen-labelling-technical-guidance.pdf |date=2017-07-07 }} (April 2015).</ref><ref name=FDAreadlabel2017 /><ref name="FSIS2017">{{cite web|title=Food Ingredients of Public Health Concern|url=https://www.fsis.usda.gov/wps/wcm/connect/09708e0b-1c79-43b4-99c4-78e408d01df1/35_IM_Ingredients_Health_Concern.pdf?MOD=AJPERES|archive-url=https://web.archive.org/web/20150729012550/http://www.fsis.usda.gov/wps/wcm/connect/09708e0b-1c79-43b4-99c4-78e408d01df1/35_IM_Ingredients_Health_Concern.pdf?MOD=AJPERES|url-status=dead|archive-date=July 29, 2015|website=United States Department of Agriculture. Food Safety and Inspection Service.|access-date=16 February 2018|date=7 March 2017}}</ref><ref name="FSIS2016">{{cite web|title=Allergies and Food Safety|url=https://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-education/get-answers/food-safety-fact-sheets/food-labeling/allergies-and-food-safety/allergies-and-food-safety|archive-url=https://web.archive.org/web/20130915060328/http://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-education/get-answers/food-safety-fact-sheets/food-labeling/allergies-and-food-safety/allergies-and-food-safety|url-status=dead|archive-date=September 15, 2013|website=United States Department of Agriculture. Food Safety and Inspection Service.|access-date=16 February 2018|date=1 December 2016}}</ref><ref name=Allen2014 /><ref name=FDAallergies2017 />

====Ingredients intentionally added====
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.<ref name=FDA2004 /> This list originated in 1999 from the World Health Organisation Codex Alimentarius Commission.<ref name=Allen2014 /> 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).<ref name=FDA2004 /><ref name=FDAreadlabel2017>{{cite web|last=FDA|title=Have Food Allergies? Read the Label|website=[[Food and Drug Administration]]|url=https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm254504.htm|archive-url=https://web.archive.org/web/20110514051624/http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm254504.htm|url-status=dead|archive-date=May 14, 2011|date=14 December 2017|access-date=14 January 2018}}</ref> The European Union requires listing for those eight major allergens plus molluscs, celery, mustard, lupin, sesame, and sulfites.<ref name=EU2015 />

In January 2025, the FDA issued guidance reducing the number of tree nuts that require food allergen labeling under FALCPA.<ref>{{Cite web |last= |first= |date=2025-03-26 |title=Guidance for Industry: Questions and Answers Regarding Food Allergen Labeling (Edition 5) |url=https://www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-industry-questions-and-answers-regarding-food-allergen-labeling-edition-5 |access-date=2025-06-17 |website=www.fda.gov |language=en}}</ref> Under this guidance, [[coconut]], [[Kola nut|cola (kola) nut]], beech nut, butternut, [[chestnut]], [[Quercus muehlenbergii|chinquapin]], [[Ginkgo biloba|ginkgo nut]], [[Hickory|hickory nut]], palm nut, [[Canarium ovatum|pili nut]], and shea nut no longer require a "Contains: tree nuts" statement. However, [[almond]], black walnut, [[Brazil nut]], California walnut, [[cashew]], [[hazelnut]], heartnut (Japanese walnut), [[Macadamia|macadamia nut]], [[pecan]], [[pine nut]], [[pistachio]], and English and Persian walnut must still be labeled by FALCPA standards.<ref>{{Cite web |date=2025-06-13 |title=Update to FDA Guidance for Food Allergen Labeling - FoodAllergy.org |url=https://www.foodallergy.org/fare-blog/update-fda-guidance-food-allergen-labeling |archive-url=https://web.archive.org/web/20250526082606/https://www.foodallergy.org/fare-blog/update-fda-guidance-food-allergen-labeling |archive-date=2025-05-26 |access-date=2025-06-17 |website=www.foodallergy.org |language=en}}</ref>

FALCPA applies to packaged foods regulated by the [[Food and Drug Administration|FDA]], which does not include poultry, most meats, certain egg products, and most alcoholic beverages.<ref name=FDAallergies2017 /> 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.<ref name="FSIS2017" /><ref name="FSIS2016" />  FALCPA also does not apply to food prepared in restaurants.<ref name="pmid24505841">{{cite journal| author=Roses JB| title=Food allergen law and the Food Allergen Labeling and Consumer Protection Act of 2004: falling short of true protection for food allergy sufferers. | journal=Food and Drug Law Journal| year= 2011 | volume= 66 | issue= 2 | pages= 225–42, ii | pmid=24505841 }}</ref><ref name="FDAFALCPAquestions">{{cite web|last=FDA|title=Food Allergen Labeling And Consumer Protection Act of 2004 Questions and Answers |website=[[Food and Drug Administration]] |url=https://www.fda.gov/Food/GuidanceRegulation/GuidanceDocumentsRegulatoryInformation/Allergens/ucm106890.htm |archive-url=https://web.archive.org/web/20130318054344/http://www.fda.gov/Food/GuidanceRegulation/GuidanceDocumentsRegulatoryInformation/Allergens/ucm106890.htm |url-status=dead |archive-date=March 18, 2013 |date=18 July 2006|access-date=12 March 2018}}</ref> 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.<ref>{{cite web |url=http://www.food.gov.uk/business-industry/allergy-guide |title=Allergy and intolerance: guidance for businesses |access-date=2014-12-12 |url-status=live |archive-url=https://web.archive.org/web/20141208003515/https://www.food.gov.uk/business-industry/allergy-guide |archive-date=2014-12-08 }}</ref>

====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.).<ref name=Allen2014 /><ref name=FDAallergies2017>{{cite web|last=FDA|title=Food Allergies: What You Need to Know |website=[[Food and Drug Administration]] |url=https://www.fda.gov/Food/ResourcesForYou/Consumers/ucm079311.htm |archive-url=https://web.archive.org/web/20090607081658/http://www.fda.gov/Food/ResourcesForYou/Consumers/ucm079311.htm |url-status=dead |archive-date=June 7, 2009 |date=18 December 2017|access-date=12 January 2018}}</ref> 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.<ref name=Mills2004>{{cite journal |vauthors=Mills EN, Valovirta E, Madsen C, Taylor SL, Vieths S, Anklam E, Baumgartner S, Koch P, Crevel RW, Frewer L |title=Information provision for allergic consumers--where are we going with food allergen labelling? |journal=Allergy|volume=59 |issue=12 |pages=1262–1268 |year=2004 |pmid=15507093 |doi=10.1111/j.1398-9995.2004.00720.x |s2cid=40395908 }}</ref><ref name=Taylor2015>{{cite book |vauthors=Taylor SL, Baumert JL |title=Food Allergy: Molecular Basis and Clinical Practice |chapter=Worldwide food allergy labeling and detection of allergens in processed foods |volume=101 |pages=227–234 |year=2015 |pmid=26022883 |doi=10.1159/000373910 |series=Chemical Immunology and Allergy |isbn=978-3-318-02340-4 }}</ref>

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.<ref name=Allen2014>{{cite journal |vauthors=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 |title=Precautionary labelling of foods for allergen content: are we ready for a global framework? |journal=World Allergy Organization Journal|volume=7 |issue=1 |pages=1–14 |year=2014 |pmid=24791183 |pmc=4005619 |doi=10.1186/1939-4551-7-10 |doi-access=free }}</ref><ref name=DunnGalvin2015>{{cite journal |vauthors=DunnGalvin A, Chan CH, et al. |title=Precautionary allergen labelling: perspectives from key stakeholder groups |journal=Allergy|volume=70 |issue=9 |pages=1039–1051 |year=2015 |pmid=25808296 |doi=10.1111/all.12614 |s2cid=18362869 |doi-access=free }}</ref> PAL labeling can be confusing to consumers, especially as there can be many variations on the wording of the warning.<ref name=DunnGalvin2015 /><ref name=Zurzolo2016>{{cite journal |vauthors=Zurzolo GA, de Courten M, Koplin J, Mathai ML, Allen KJ |title=Is advising food allergic patients to avoid food with precautionary allergen labelling out of date? |journal=Current Opinion in Allergy & Clinical Immunology|volume=16 |issue=3 |pages=272–277 |year=2016 |pmid=26981748 |doi=10.1097/ACI.0000000000000262 |s2cid=21326926 }}</ref> {{As of|2014}} PAL is regulated only in Switzerland, Japan, Argentina, and South Africa. Argentina decided to prohibit precautionary allergen labeling in 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.<ref name=Allen2014 /> 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 what might be accidentally in a food product beyond "may contain."<ref name=Allen2014B>{{cite journal |vauthors=Allen KJ, Remington BC, Baumert JL, Crevel RW, Houben GF, Brooke-Taylor S, Kruizinga AG, Taylor SL |title=Allergen reference doses for precautionary labeling (VITAL 2.0): clinical implications |journal=Journal of Allergy and Clinical Immunology|volume=133 |issue=1 |pages=156–164 |year=2014 |pmid=23987796 |doi=10.1016/j.jaci.2013.06.042 |doi-access=free }}</ref><ref>{{cite journal |vauthors=Taylor SL, Baumert JL, Kruizinga AG, Remington BC, Crevel RW, Brooke-Taylor S, Allen KJ, Houben G |title=Establishment of Reference Doses for residues of allergenic foods: report of the VITAL Expert Panel |journal=Food and Chemical Toxicology|volume=63 |pages=9–17 |year=2014 |pmid=24184597 |doi=10.1016/j.fct.2013.10.032 }}</ref> VITAL 2.0 was developed by the Allergen Bureau, a food industry sponsored, non-government organization.<ref>[http://allergenbureau.net/vital/ The VITAL Program] Allergen Bureau, Australia and New Zealand.</ref> The European Union has initiated a process to create labeling regulations for unintentional contamination, but is not expected to publish such before 2024.<ref>{{cite journal |vauthors=Popping B, Diaz-Amigo C |title=European Regulations for Labeling Requirements for Food Allergens and Substances Causing Intolerances: History and Future |journal=Journal of AOAC International|volume=101 |issue=1 |pages=2–7 |year=2018 |pmid=29202901 |doi=10.5740/jaoacint.17-0381 |doi-access=free }}</ref>

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, [[almond]]s, [[hazelnut]]s, [[cashew|cashew nuts]], [[Brazil nut]]s, [[macadamia|macadamia nuts]], [[walnut]]s, [[pecan|pecan nuts]], [[pistachio|pistachios]], [[pine nut]]s, and [[chestnut]]s.<ref name="ANVISA2016"/>

==Society and culture==
Food fear has a significant impact on the quality of life.<ref name=Lange2014/><ref name=Velde2013/> For children with allergies, 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.<ref>{{cite journal |vauthors=Fong AT, Katelaris CH, Wainstein B |title=Bullying and quality of life in children and adolescents with food allergy |journal=Journal of Paediatrics and Child Health|volume=53 |issue=7 |pages=630–635 |year=2017 |pmid=28608485 |doi=10.1111/jpc.13570 |s2cid=9719096 }}</ref>

==Research==
[[Immunotherapy]] treatments are being developed for tree nut allergy, including oral immunotherapy, sublingual immunotherapy, and epicutaneous immunotherapy.<ref name="WeinbergerSicherer2018" />

== See also ==
* [[Allergy]] (has diagrams showing involvement of different types of white blood cells)
* [[Food allergy]] (has images of hives, skin prick test, and patch test)
* [[List of allergens]] (food and non-food)
* [[Peanut allergy]] (can be cross-reactive to tree nut allergy)

==Notes==
{{reflist|group=note}}

== References ==
{{Reflist}}

== External links ==
{{Medical resources
|  DiseasesDB     = 
|  ICD10          = 
|  ICD9           = {{ICD9|995.64}}, {{ICD9|V15.05}}
|  ICDO           = 
|  OMIM           = 
|  MedlinePlus    = 
|  eMedicineSubj  = 
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|  MeshID         = D021184
}}
* [http://www.faiusa.org/?page=treenuts Tree nut allergy] at [[Food Allergy Initiative]]
* [http://well.blogs.nytimes.com/2008/12/15/are-nut-bans-promoting-hysteria/ "Are Nut Bans Promoting Hysteria?"] by Tana Parker-Pope at ''The New York Times'' (15 Dec 2008)

{{Allergic conditions}}
{{Hypersensitivity and autoimmune diseases|state=expanded}}

[[Category:Edible nuts and seeds|*]]
[[Category:Food allergies]]