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Are Food Allergies on the Rise, or Is It Misdiagnosis?iml

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iven the prevalence of news re-garding food allergy in today’smedia—from parenting blogs

hat debate whether schools shouldan nuts and peanut butter, to thechool bus that was evacuated andecontaminated after someone saw aeanut on the floor (1), to the 2007eport of a child in the United King-om barred from school because ad-inistrators deemed his nut allergy aealth and safety hazard (2)—itight be assumed that a large num-

er of individuals suffer from food al-ergy. In fact, although the Centersor Disease Control and Preventionave reported that in the Unitedtates, from 1997 to 2007, food aller-ies in children rose 18% (3,4), only amall percentage of the population—pproximately 4% to 8% of childrennd roughly 2% of adults (5)—haveiagnosed food allergies.Researchers are confounded by this

ncrease in food allergy diagnosis andy another puzzling proliferation: aecent uptick in misdiagnosis. Beingnnecessarily subjected to social bur-ens of allergy aside, there may beerious medical consequences to ad-ering to a needlessly restrictive di-t—that is, if a child has needlesslyvoided a given food because of thearents’ allergy fears—it has beenuggested that a sensitivity to thatood could develop if it is ultimatelyonsumed later. Similarly, an adultxperiencing gastrointestinal prob-ems may self-diagnose the onset ofood allergy or receive faulty medicaldvice based on unreliable tests. Fur-hermore, because the terms food al-ergy, food intolerance, and food sen-itivity are frequently and often

This article was written by KarenStein, MFA, a freelance writer inQuerétaro, México. Stein is aformer editor of the Journal andhas also taught English andcomposition at the academic level.She currently runs a center forteaching English in México.

fdoi: 10.1016/j.jada.2009.09.019

832 Journal of the AMERICAN DIETETIC ASSOCIATI

ncorrectly used interchangeably,isunderstanding of the actual prob-

em is possible.Because registered dietitians (RDs)ill likely encounter patients seekingietary counseling for suspected or di-gnosed food allergies, they must beware of current considerations whendvising patients and clients regard-ng food allergies, both real and mis-iagnosed, while also taking into ac-ount individual needs.

HE PROBLEM WITH TESTINGn the early 1980s, conflict regardingow to define a true allergy existed,ith “some physicians (who usually

are for children) ascrib[ing] a stag-ering array of symptoms to food-tuffs” whereas “others (who usuallyare for adults) seem[ed] unwilling toonsider any food reaction ’allergic’xcept for acute anaphylactic reac-ions” (6), leading to a “dubious repu-ation” for the subject of food allergyltogether. An emphasis on testingas encouraged, though questions of

eliability persisted.Despite improvements, unease

bout the dependability of food al-ergy test results are still an issue, asalse-positives and even false-nega-ives are entirely possible. Intrader-al testing for food allergy, for in-

tance, is not advised because it has aigh rate of false-positives, and skinrick test results can be affected if theatient has recently taken antihista-ine (7). It has been noted that a

ombination of skin prick testing plusllergy patch testing could help withdentification of food allergens, butalse-positive results are still a con-ern (8). Complicating matters is thathen a test reveals higher serum lev-ls of allergen-specific immunoglobu-in-E (s-IgE) antibodies, it only re-eals probability of a reaction to foodnd not clinical relevance (7); accord-ngly, a patient may test positive for-IgE to a food, but this does not nec-ssarily mean that there is clinicalllergy and that that patient will suf-

er adverse effects from consuming s

ON © 2009

hat food (9). Furthermore, when anllergy test reveals sensitization, itoes not indicate whether the s-IgE ishe actual cause of the symptoms9,10). In fact, s-IgE has “suboptimalredictive values” (8). Thus, the selec-ion of which allergens to test shouldctually be based on patient history—symptoms, environmental and occu-ational exposures, age, and otherelevant factors”—and not random;ny food that a patient has toleratedhould not be tested. A false-negatives possible if inflammatory responseo a food does not occur in an IgE-ediated immune mechanism (9).For these reasons, diagnostic tests

hould not be considered the meansor determining presence of allergyut “should be used to support or ex-lude a diagnosis of specific allergiesased on the history” (9). It should beoted that the most common aller-ens are cow’s milk, egg, soy, wheat,eanut and tree nuts, fish, and shell-sh; children are most frequently al-

ergic to cow’s milk, egg, peanut, soy,heat, and fish, whereas adults re-

pond most often to peanut, tree nut,sh, and shell fish (7). However, aller-ic response can be set off by any foodthough allergy to chocolate, citrus,erries, and corn are unusual) (9).Food additives—most frequently

nnatto, carmine, and saffron—maylso be suspect for causing an adverseeaction in patients, though theyhouldn’t be considered until all po-ential food allergens have been ruledut. Food additives are usually iden-ified as a potential trigger if a pa-ient’s history of adverse reactioneems to be caused by unrelated foodsr if a specific food is normally toler-ted only if prepared at home (11).owever, prevalence of food additivellergy is low, and there is littlegreement in the literature regardinghe signs and approximate pervasive-ess, as reliable studies in this areare scant (11). For instance, monoso-ium glutamate, or MSG, has longeen associated with allergic re-

ponse in restaurant settings, partic-

by the American Dietetic Association

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TOPICS OF PROFESSIONAL INTEREST

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834 November 2009 Volume 109 Number 11

larly in establishments that servesian dishes. But despite descrip-

ions of moderate to severe reaction tohe alleged offending food, double-lind challenges failed to establish aink and reactions were “inconsistentnd not reproducible” (11). Further-ore, in the case of tartrazine—D&C yellow no. 5—which is com-only used in sweets and has been

inked to a few cases of asthma andrticaria, challenge testing has dem-nstrated that the claims of allergicesponse have far outnumbered theonfirmed cases (11).Oral food challenges, whereby

small doses of food are administeredn gradually increasing amounts untilfull serving of the allergen has been

ngested” as vital signs and target or-ans are monitored (7), are a recom-ended tool for confirmation of diag-

osis.Diagnosis must be confirmed not

nly because of the terrifying possibil-ty of anaphylactic shock—which maynvolve a combination of the gastroin-estinal tract, the skin, respiratoryract, and cardiovascular system—ut because of the possibility of mis-nderstanding the body’s response tofood, whether by the individual who

onsumed the food, a family member,r even a health care professional.

IAGNOSIS AND MISDIAGNOSIShe burden of food allergy can bereat. Among 87 families with chil-ren with food allergy, 60% indicatedhat family social activities were af-ected and one third noted that schoolttendance had been negatively af-ected (12). One might assume, then,hat a number of families are need-essly put through such challenges:lthough the incidence of clinical foodllergy in the population is quite low,ome studies have found that parentselieve that, among children youngerhan age 3, 28% to 43% have a foodllergy (12), whereas another studyound that 10% to 20% of the publichinks that a family member or theyhemselves have a food allergy (13);nd, one fourth of US households re-orted dietary habit modification toespect a family member’s food al-ergy (12). Furthermore, childrenith peanut allergy have been found

o be anxious about being away from

ome, more fearful of adverse health t

ffects beyond the allergy, and re-trictive of their physical activity (12).What accounts for the discrepancy

n actual numbers versus the overre-ction in the public? One contributingactor is that the characterization oflinical allergy is largely misunder-tood by the public—who may beuick to ascribe nasal congestion,tomach pain, and headaches as a re-ction to food (14)—and professionalsho misread serum test results,hich can overestimate or underesti-ate the body’s response or “fail to

istinguish between similar proteinsn different foods” (4).

A reaction to food is deemed allergynly if it occurs as an immune re-ponse, but some foods—includingpoiled fish, most notably tuna, mack-rel, mahi-mahi, and bluefish, andheeses—can release bacteria thatause histamine conversion thatimics the effects of food allergens

13).If a negative response is not associ-

ted with the immune system, then its likely a food intolerance or sensitiv-ty—though, as noted previously,hese designations are frequentlysed as inaccurate synonyms for foodllergy in the medical literature anday press. Intolerance is frequentlyhe term used, because—as “food al-ergy has no pathognomonic ornique symptoms . . . food may not be

nvolved at all . . . [and] the mecha-ism may not be immunologic”—us-

ng the catchall helps to “avoid theask of sorting out the underlyingechanism” (10).Food intolerance may be caused byetabolic defect, as in the case of lac-

ose intolerance, or food idiosyncrasy,r “adverse reactions to foods or foodomponents that occur through un-nown mechanisms and which canven include psychosomatic illness”13). Or, the body’s reaction couldven be the result of food poisoning. A008 salmonella outbreak tied to aeanut processing plant demon-trated that diarrhea or vomiting af-er consuming peanuts is not alwaysn immunologic response.

elf-Diagnosismajor difficulty in the proliferation

f self-diagnosis or diagnosis of chil-ren by parents is that “they are oftenrroneous, leading to the identifica-

ion of the wrong foods, and implicate

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TOPICS OF PROFESSIONAL INTEREST

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oo many foods” (13). In addition, vi-amin and mineral deficiencies (14)nd undernutrition or malnutrition10), resulting from restrictive dietso eliminate offending foods, withoutnput from an RD, can occur.

ethinking Food Allergy Policiess individuals and families unneces-arily avoid foods out of fear of allergyr misdiagnosis—and as studies areeginning to show that early expo-ure to foods, rather than abstentionrom them, could reduce the risk ofllergy (1)—medical organizationsre beginning to rethink their policiesegarding food allergies. For example,he American Academy of Pediatricsas reversed its earlier stance that anxpectant mother should avoidnown food allergens while pregnant15). Another idea gaining momen-um is that the increase in sensitivityay be related to the postponement

f introducing certain items to the di-t—that is, although it has been pre-iously advised to wait until childrenave reached a particular age groupo allow them to eat specific foods,erhaps this delay is the cause of ul-imate sensitivities. Thus, the Amer-can Academy of Asthma, Allergy,nd Immunology, has convened aommittee tasked with determininghether postponing introduction ofggs, peanuts, and shellfish until ahild’s second or third birthday re-ains the best recommendation (4).

NEW LOOK AT NUTSlthough the number of Americansllergic to seafood (6.9 million) isore than double the number allergic

o peanuts (3.3 million), peanuts arerequently considered as one of theajor threats to child safety, particu-

arly among parents of school-agedhildren. Yet, out of 30 million hospi-alizations across the United Statesach year, only 2,000 are related to andverse event caused by food allergy1). And out of every 100 Americanshose skin test for peanut allergyields a positive result, only five haveclinical allergy to peanuts (7).So as some organizations are recon-

idering their statements and guide-ines that address food allergy, sev-ral critics have publicly commentedn the extreme degree to which pea-

ut allergy is accommodated in to- f

836 November 2009 Volume 109 Number 11

ay’s society. Nicholas A. Christakis,D, a physician and Harvard Univer-

ity professor of medical sociology,hile acknowledging the medical se-

iousness of true peanut allergy, lik-ns the peanut panic to mass psycho-enic illness, or epidemic hysteria, “aocial network phenomenon involvingtherwise healthy people in a cascadef anxiety” that, in the case of pea-uts, leads to “well intentioned effortso reduce exposure to nuts [that] ac-ually fan the flames, since they sig-al to parents that nuts are a clearnd present danger. This encouragesore parents to worry, which fuels

he epidemic. It also encourages morearents to have their children tested,hus detecting mild and meaninglessallergies’ to nuts” (1). And, Chris-akis argues, the outcome at risk ishat children develop hypersensitiza-ion to nuts via needless avoidance.

Even if it is true that individualsre causing their own allergies, someood news is that not all allergies areermanent. Individuals can eventu-lly develop tolerance of some foods—ost commonly milk, egg, soy, andheat—whereas allergies to seafood,uts, and peanuts tend to persist. Inarch 2009, at the meeting of themerican Academy of Allergy,sthma, and Immunology, a presen-

ation announced the unpublished re-ults of clinical trials in which fiveeanut-allergic children seeminglyad overcome their allergies by “con-uming tiny but increasing doses ofhe food” (3). Studies testing the ef-ects of food allergy herbal formulaFAHF)-1 and FAHF-2 found thatAHF-1 protected mice from anaphy-

axis caused by peanut allergyhereas FAHF-2 prevented it; clini-

al trials in the United States haveegun to determine if FAHF-2 is theptimal botanical drug for treatingeanut allergy as well as other IgE-ediated food allergies (16). Re-

earchers hope that these results willead to peanut allergy treatment inhe next few years; in addition, in009, investigators are expected toegin human clinical trials on a vac-ine “designed to trick the immuneystem into giving up its defensegainst peanuts” (3).It is possible, however, that allergy

uppression therapies will not lead tomass influx of nouveau consumers

f peanuts: In a study of patients with

ood allergies, some individuals con- m

inued to avoid that food even afterood challenges yielded no immuno-ogic response (12). Still, patients andlients should be made aware by theirDs that consumption of the previ-usly offending food must be contin-ed, in reasonable amounts, if toler-nce is to be maintained.

Ds AND FOOD ALLERGYespite the progress being made, at

his time there are no known reliableherapies for overcoming food allergy11). Thus, abstention from the foodllergens is the principal counsel pa-ients currently receive. However, be-ause self-diagnosis among individu-ls is increasingly common, RDspproached by patients or clients re-arding elimination diets to addressn allergy should be encouraged toursue confirmation via testing by aoard-certified allergist (12). Patientsith food allergy will most likelyresent with the following symptomsfter consuming specific foods: hivesr itchy red skin; congested or itchyose, sneezing, coughing, tightening ofhroat, worsening of asthma symp-oms, or itchy, watery eyes; vomiting,tomach cramps, or diarrhea; andwelling (17).Because an allergic response to food

an be fatal, it is essential that a foodllergy be diagnosed. But because ofhe social challenges of maintaining aestrictive diet, it is equally essentialo be certain that a diagnosis reflects

true allergy. According to Dinaronson, MS, RD, president of Well-

ech Solutions in Montclair, NJ, ando-author of Food Allergy Survivaluide: Surviving and Thriving withood Allergies and Sensitivities,Given that food sensitivities (allergynd/or intolerance) are extremelyomplex and involve multiple bodyystems, and that they are highly in-ividual in their etiology and sever-ty, we must evaluate test results forhat they are: only one piece of auch larger puzzle.” A negative test

esult does not necessarily prove aack of food sensitivity, Aronson says,hough she believes that “it is impor-ant to step outside the paradigm thatandates that there has to be a pos-

tive test” for determining the pres-nce of food sensitivity. However, be-ause “50% of positive skin prick testsre false-positives,” Aronson recom-

ends starting with conservative

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TOPICS OF PROFESSIONAL INTEREST

esting but switching to different test-ng if the first tests do not diagnose oruccessfully resolve the problem.Lynn Christie, MS, RD, research

roject manager dietitian in the Pedi-tric Allergy and Immunology De-artment at Arkansas Children’sospital, Little Rock, agrees and

omments that although IgE-medi-ted disease can have serious conse-uences, “the IgE tests are helpfulieces of the puzzle and need to benterpreted in the context of a clinicalistory in order to diagnose an IgE-ediated food allergy.”Furthermore, Christie notes, the

ests available are not exhaustive inerms of addressing all potential al-ergens; for instance, food dye testings limited to only natural additivesuch as annatto, carmine, and saf-ron. Christie says, “If the familyhinks a child is allergic to an artifi-ial food dye, there is no test. And ifhey think the symptoms interfereith the child’s quality of life, they

an eliminate the dye [from thehild’s diet].” In this case, she pointsut, some processed foods will beliminated from the diet, and the nu-ritional composition of the child’siet will not be adversely affected.But food avoidance can be less than

deal when nutritional composition isompromised, and, as noted previ-usly, individuals frequently continueo avoid foods even after food chal-enges have failed to establish a defi-ite physiological response. In theseases, Aronson believes this issueould be beyond the scope of the prac-ice of the RD. Addressing a patient’sood behaviors “requires knowledge insychology and behavior, and we areot all trained behavior specialists,”he says, adding, “We can only go soar as to inform clients of risks andenefits. If they still refuse, and theyave probable psychological issues,hose issues need to be addressed byn appropriate therapist.”However, explains Christie, oral

ood challenges can also help to ad-ress any fears related to foods tohich an individual previously hasad sensitivity. In these double-blind,lacebo-controlled food challenges, anndividual consumes two servings—ne containing the food in question—nd if he or she doesn’t experience aeaction, a normal serving of that foods administered. “This is one of the

est ways to help the person accept

he new food,” says Christie, adding,When the individual eats the food insafe environment and realizes noth-

ng happened, it helps with the psy-hological aspect.”For patients at square one, RDs can

ssist allergists and patients in com-leting a highly detailed food historyor determining “possible food symp-om relationships, suspect foods andngredients, and patient dilemmashat may complicate food allergenvoidance,” as well as creating diettrategies for short-term and long-erm avoidance of the culprit foodshile maintaining nutritional ade-uacy (18). However, Aronson adviseshat an RD who does not want to workith a client complaining of food sen-

itivities should refer him or her to anD with expertise in that area.Aronson also notes that although

ncreasing food-allergic individuals’xposure to the offending foods hashown to increase tolerance in a sub-tantial number of people, it has notet been accepted as an incontrovert-ble fact that avoidance increases riskr that early exposure prevents al-ergy development.

But among the most importanthings an RD can do for the poten-ially food-allergic patient is to workith him or her in determining a

ourse of action for wellness. Thoughelf-diagnosis is frequently scoffed atn the press and perhaps amongealth care professionals, its notedropagation should not be used forudging the patient or client if allergyesting does not reveal the root causef that patient’s physiological re-ponse to food. It is essential, saysronson, that clients always be takeneriously. “It is not within ourights—nor is it consistent with themerican Dietetic Association’s Codef Ethics—to write off a complaint as

psychological’ or ’in the client’s head,’s many clinicians unfortunately do.”

eferences1. Christakis NA. The allergies hysteria is just

nuts. BMJ. 2008;337:a2880.2. Ahmed M. Nut allergy boy barred from

school as a “health hazard.” The Times. Sep-tember 28, 2007. http://www.timesonline.co.uk/tol/life_and_style/education/article2547541.ece. Accessed May 31, 2009.

3. Healy M. Therapy to suppress peanut aller-gies is reported. Chicago Tribune. March 16,2009. http://www.chicagotribune.com/la-sci-peanut16-2009mar16,0,401231.story. Ac-

cessed May 31, 2009.

4. Parker-Pope T. Telling food allergies from

November 2009 ● Journal

false alarms. New York Times. February 3,2009. http://www.nytimes.com/2009/02/03/health/03well.html. Accessed May 1, 2009.

5. Centers for Disease Control and Prevention.Food allergies. Centers for Disease Controland Prevention Web site. http://www.cdc.gov/healthyyouth/foodallergies/. Accessed May 31,2009.

6. Bierman CW, Furukawa CT. Food allergy.Pediatr Rev. 1982;3:213-220.

7. Kim JS. Food allergy: Diagnosis, treatment,prognosis, and prevention. Pediatr Ann.2008;37:546-551.

8. Bahna SL. Reflections on current food al-lergy controversies: Specific sIgE test appli-cation, patch testing, eosinophilic esophagi-tis, and probiotics. Allergy Asthma Proc.2008;29:447-452.

9. Cox L, Williams B, Sicherer S, OppenheimerJ, Sher L, Hamilton R, Golden D; AmericanCollege of Allergy, Asthma and ImmunologyTest Task Force; American Academy of Al-lergy, Asthma and Immunology Specific IgETest Task Force. Pearls and pitfalls of al-lergy diagnostic testing: Report from theAmerican College of Allergy, Asthma andImmunology/American Academy of Allergy,Asthma and Immunology Specific IgE TestTask Force. Ann Allergy Asthma Immunol.2008;101:580-592.

0. Bahna SL. Food allergy and intolerance:Guest editorial. Pediatr Ann. 2006;35:690-693.

1. Randhawa S, Bahna SL. Hypersensitivity tofood additives. Curr Opin Allerg Clin Immu-nol. 2009;9:278-283.

2. Meerschaert CM. Food allergy: A look attraditional and complementary diagnosisand treatment. Today’s Dietitian. 2007;9:40.

3. Taylor SL, Hefle SL. Food allergies andother food sensitivities: A publication of theInstitute of Food Technologists’ ExpertPanel on Food Safety and Nutrition. FoodTechnol. 2001;55:68-83.

4. Dietitians warn against self-diagnosed foodallergies. Medical News Today Web site.Published February 14, 2008. http://www.medicalnewstoday.com/articles/97300.php.Accessed May 1, 2009.

5. Greer FR, Sicherer SH, Burks AW, Commit-tee on Nutrition and Section on Allergy andImmunology. Effects of early nutritional in-terventions on the development of atopic dis-ease in infants and children: the role of ma-ternal dietary restriction, breastfeeding,timing of introduction of complementaryfoods, and hydrolyzed formulas. Pediatrics.2008;121:183-191.

6. Srivastava KD, Qu C, Zhang T, Goldfarb J,Sampson HA, Li X-M. Food allergy herbalformula-2 silences peanut-induced anaphy-laxis for a prolonged posttreatment periodvia IFN-�-producing CD8� T cells. J ClinAllergy Immunol. 2009;123:443-451.

7. American Academy of Allergy, Asthma, andImmunology. Diseases 101: Food allergy.American Academy of Allergy, Asthma, andImmunology Web site. http://www.aaaai.org/patients/gallery/foodallergy.asp. AccessedMay 3, 2009.

8. Hubbard S. Nutrition and food allergies: Thedietitian’s role. Ann Allergy Asthma Immu-nol. 2003;90:115-116.

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