18 August-September 2007 www.igliving.com IG Living!

I t was a summery August night,and Emma was talking withfriends and enjoying fresh-cut

watermelon. The next morning, shewoke up to get ready for work andcould hardly open her eyes. Her eye-lids were swollen and her neck wascovered in hives. She knew that shewas allergic to ragweed pollen, butshe did not recall being allergic towatermelon. What do you think hap-pened to Emma? Could it have beenprevented? Was this a food allergy?

According to the Food Allergyand Anaphylaxis Network (FAAN),approximately 12 million Americanssuffer from food allergies. As manyas 30,000 individuals require emer-gency room treatment for severefood allergies or anaphylaxis eachyear. This impacts general healthand emotional well-being.

Syed Arshad, MD, is director ofthe David Hide Asthma and AllergyResearch Centre at St. Mary’s Hospital,in Newport, Isle of Wight, U.K. Hedescribes food allergies as a signifi-cant problem that is not going away.In particular, he says, “there has beenan increase in peanut allergies…which tends to be the most danger-ous.” He suggests that food allergiesare common, afflicting up to 8 percentof young children and 4 percent ofolder children and adults.

What Are Food Allergies?Most of us have probably encoun-

tered someone with Emma’s foodallergy—the type that is provokedby exposure, and re-exposure, to acertain food ingredient or substance.The body mistakenly learns that afood component is harmful. Then,the immune system takes action bylaunching its weaponry. For example,the body may think that pollen is aninfection that needs to be destroyed.What happens next? The body mayrespond with immunoglobulin E (IgE)antibodies and release compounds,such as histamine, that cause symp-toms from mild itchiness to runny noseto atopic dermatitis to sudden deathdue to anaphylactic shock. Various

organs such as the skin, gastrointesti-nal tract and respiratory tract becomeirritated or injured by this process.

The European Academy of Allergyand Clinical Immunology Task Forcesuggests that adverse reactions tofood should be called “food hyper-sensitivity” (see Figure 1). When theimmune system is involved, theappropriate term is “food allergy.”This is typically, but not always, drivenby IgE antibodies. The task forcesuggests that other reactions,sometimes referred to as “foodintolerance” (e.g., lactose intolerance),should be referred to as “non-allergicfood hypersensitivity.” Severe, general-ized allergic reactions to food areclassified as anaphylaxis.1

Food Hypersensitivity

Food Allergy

IgE Mediated• Infantile• Tree nut and peanut• Pollen-associated

Non-Allergic Food Hypersensitivity• Lactose intolerance • Sugar intolerance (fructose or sucrose)• MSG symptom complex• Sulfite sensitivity• Others

Non-IgE Mediated & Mixed • Eosinophil-associated gastrointestinal disease• Celiac disease • Protein enterocolitis syndrome • Protein proctitis • Protein enteropathy

What is food to one man is bitter poison to others.

— Lucretius (99 BC – 55 BC)

Understanding By Jessica Schulman, PhD, MPH, RD

Figure 1. Food Hypersensitivity and Food Allergy

1 Adapted from: Nomenclature Revised by the European Academy of Allergology and Clinical Immunology, [Johansson et al. 2001] and theWorld Allergy Association [Motala, 2007].

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Ulrich Wahn, MD, director of theDepartment of Pediatric Pneumologyand Immunology at the University ofBerlin, suggests that, for the generalpopulation, eight foods account for90 percent of all food-allergic reac-tions: milk, egg, peanut, tree nut(walnuts, almonds, cashews, pista-chios, pecans, etc.), fish, shellfish,soy and wheat. Dr. Wahn providesa road map for understanding IgE-driven food allergies.

1. Infantile: Infantile food allergybegins early in life, around 6 to 12months of age. It is generally tran-sient, so it gets better over a periodof months or a limited number ofyears. Most cases run their courseby the baby’s first birthday, butsome cases last much longer.Symptoms may include vomiting,diarrhea, abdominal pain, hives,swelling, itching, eczema anddifficulty breathing. The pediatricianwill often recommend a specialformula or diet. This involvesremoving one or more items fromthe “hit list” for the baby and themother, if she is breastfeeding.Sometimes, specialized tests suchas food challenge tests or IgE levelsare ordered. The hit list includeshen eggs, cow’s milk, soy andwheat. Most young children withatopic dermatitis from food aller-gies have reactions to milk, eggsor peanuts.

2. Tree nut and peanut: These nutallergies may be life-threatening,severe and persistent throughoutlife. Early signs include a runnynose, itchy skin, hives, or tinglingin the mouth, tongue or lips. Moresevere signs include tightness inthe throat, hoarse voice, wheezing,cough nausea, vomiting and ana-phylaxis. Anaphylaxis may involveseveral symptoms at one timesuch as hives, blood pressuredrop, narrowing of the breathingtubes and swelling of the tongue.The doctor may do specializedtests to confirm the allergy. Thehit list includes cashews, almonds,pecans and walnuts among othertree nuts, and peanuts (really alegume). Although treatment fornut allergies is on the horizon,the doctor will probably recom-mend that the patient avoid thenut altogether.

3. Pollen-associated or pollen-food allergy syndrome:This syndrome can onset later in life. It may result from directexposure to pollen on a fruit orvegetable or from a cross-reactionbetween a pollen allergy and afruit or vegetable allergen. In a

cross-reaction, pollen-allergicindividuals have IgE antibodiesthat also react to allergens comingfrom a fruit or vegetable (calledcross-sensitization). For example,birch pollen allergies are associatedwith peach allergies (see Table 1).It has a wide range of severity,and symptoms are variable,including itching, uticaria or hivesand welts, burning, swelling in thelips, tongue and palate, congestion,itchy watery eyes, wheezing,nausea, abdominal pain, diarrhea,chest or throat tightness, anddifficulty swallowing or breathing.The syndrome can be persistent,and Dr. Wahn says, “The best cureis age, and you may have to waitfor decades.” The hit list includesfresh fruits and vegetables such aspears, apricots, melons, bananas,nuts such as hazelnuts or vegeta-bles such as carrots. Raw andunprocessed foods tend to causemore severe reactions.

Which food allergy did Emma mostlikely experience? If you guessedpollen-associated, you’re correct.She is allergic to ragweed pollenand developed a cross-reaction towatermelons. ➢

Food Allergies

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What Is Anaphylaxis?Anaphylactic shock is the most

severe type of food allergy: It causesdeath in 150 to 200 people annually.2

If left untreated, it can lead to deathin a matter of minutes.

On Halloween night in 2002, Gina’s2-year-old son, Conner, tasted hisfirst chocolate-coated peanut candy.He did not like the texture and spit it

onto the floor. Within a few min-utes, he was vomiting and developedfluid-filled hives that were growingand converging all over his body. Bythe time they reached the emer-gency room, the hives were aroundConner’s throat. Two epinephrineinjections were administered, one intoeach of Conner's thighs. Gina says,“Within 10 minutes' time, Conner fellasleep on his daddy's shoulder, andthe next morning the hives weregone.” A pediatric allergist offeredsome unsettling guidance. “In alllikelihood he will never be free ofthese life-threatening symptoms, sosteer clear of nuts!”

Epinephrine (adrenaline) is used forcontrolling an anaphylactic reaction.It is available as a self-injectabledevice (EpiPen®, single dose, orTwinject®, two doses). In most cases,strict avoidance of the allergy-causingfood is the only way to prevent areaction. Early administration of theepinephrine is the key to treatinganaphylaxis successfully, so, if theallergy is known, it is wise to carryepinephrine at all times.

Gina says, “Don't let the [epineph-rine] be a source of worry. Instead,use it as a confidence builder, andhelp your children to live as normala life as possible.” However, cross-contamination is a problem so Ginadoes not take Conner to places suchas ice-cream shops that may cross-contaminate with nuts. “You haveto be vigilant. Sometimes peoplehave a really difficult time graspinghow a beautiful child can have alife-threatening food allergy,” she says.

How Do You Confirm a Food Allergy?

A specialist may confirm anallergy with a food challenge inwhich a patient is given a smallamount of the substance to whichhe or she might be allergic. Dr.Wahn explains that “allergy is thedemonstration of a positive foodchallenge in an individual,” but he warns that “it is unethical tochallenge someone who has aclear-cut history of peanut allergy.”

Today, numerous allergy tests areavailable, but the most commonlyused are the skin prick test (a mos-quito bitelike bump appears if thepatient is allergic to the substance)and a blood test to check for ele-vated IgE to certain allergens ➢

Pollen or Inhalant Common Food Allergens

Birch pollen

Mugwort pollen

Ragweed pollen

Latex (hevea brasiliensis tree, rubber tree)

Apple, raw potato, carrot, celery, hazelnut, pear, peach, plum, cherry

Celery, apple, peanut, kiwi fruit, carrot, parsley, spices (fennel, coriander, aniseed, cumin)

Melons (e.g., watermelon, cantaloupe, and honeydew), bananas

Avocado, kiwi fruit, chestnut, papaya, banana

* Adapted from the World Allergy Organization

2 FAAN, 2002.

Table 1. Cross-reaction Allergies*

Conner and his mother, Gina

Epinephrine pen

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Allergic eosinophilic gastrointestinal disease is a mixedphenomenon involving IgE antibodies and other immunecomponents, such as T cells. This is an emerging disorderthat is linked to food allergies and an irregular immunesystem. Buddy’s story, below, may serve as a model forunderstanding how other parts of the immune systeminteract to cause allergic disease. If there is suspicionof a problem, always work through the process ofmaking the correct diagnosis with your doctor—andbe persistent.

Buddy’s StoryBy 5 weeks of age, Buddy had projectile vomiting and

diarrhea while being breastfed, a horrible skin rash on hisbottom, and he was generally irritated. “He spent his firstyear strapped into his car seat next to my bed becausewe were afraid that if we laid him down he would throwup and suffocate on his own vomit,” recalls Buddy’s mother,Nancy. “Some days, he would cry and scream in pain for14 hours straight.”

When I asked Nancy what steps she took to get himcorrectly diagnosed and treated, she said, “For the next14 months, we went to our pediatrician, ENT, pulmonologist,allergist, immunologist, surgeon and gastroenterologist.”No one was able to see the whole picture, and the familycontinued to suffer. “I went through endless amounts ofexpensive medicines to no avail. I tried numerous formulasand restricted my own diet, since I was breastfeeding.Even simple things like going to the grocery store wereimpossible. He would scream in pain, and everyone wouldlook at me as if I did something to hurt him.”

Nancy was tireless and continued to advocate for herchild. Eventually, Buddy was diagnosed with an immunedeficiency and eosinophilic enteropathy.

When Buddy was 2 years old, the family traveled 860miles from home to seek more specialized attention atCincinnati Children's Hospital Medical Center. He is nowproperly treated with a very restrictive diet and specialformula. “In the beginning, we went to no food foralmost one year and even now, at four years later, westill have periods where he cannot consume anythingbut the formula,” Nancy says.

If Buddy does not tolerate the introduction of a newfood during a food trial, it is immediately removed from

his diet and they are back to the drawing board for afew weeks or months. Every few months, Nancy doesfood trials with Buddy with the hope that perhaps oneday he will be able to eat a broader diet.

After Buddy was correctly diagnosed, he got almostimmediate relief from his symptoms. Though he still dependson a special formula, he is a happy little boy and doesn’tseem to mind his stringent diet. “The formula is bad tastingto me,” Nancy said, “but he knows, and we know, that itis safe for his body, and that is what matters.”

Buddy recently celebrated his fifth birthday. He attendspreschool part time, plays tee ball and soccer, rides hisbike without training wheels and loves to drive his bigsister nuts. Nancy explains that, with immune problemsand food allergies, the hardest part is “his problems arehidden inside of his body,” adding that “if he eats thewrong food or tries to sneak something, his body attacksitself on the inside! At any moment we could be headingto the hospital.”

What can other families learn from Buddy’s experience?“I just want parents to know that they need to followthrough with their gut feeling when something isn't right.There are many great doctors out there, but all doctorscan't be specialized in everything. Rare issues make forrare proper diagnosis,” Nancy said with conviction.

What Happened to Buddy? An eosinophil is a type of white blood cell that occurs

naturally in the human immune system—in very smallnumbers. Under certain conditions, such as when thereis an infection, the body releases a lot more eosinophilsand they accumulate in an organ such as the gut andrelease toxin. This is helpful, except when the cellsincorrectly respond to a food ingredient as if it were adeadly parasite. When this happens, the toxin damageseverything in its path, including healthy tissue. This iswhat happened to Buddy. Often, the allergic reaction isdelayed, which makes it difficult to know what to eator avoid. Symptoms vary by age. Babies will haveproblems eating, including vomiting and excruciatingpain. Adolescents and adults may have trouble swallowing.Other reported symptoms include nausea, early satietyor fullness, diarrhea, slow emptying of the stomach,blood in the stool and anemia.

Can You Say Eosinophilic?

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(e.g., radioallergosorbent tests orImmunoCap®). Patch testing is arelatively new method that is usedto determine if certain substancesare associated with inflammationof the skin. Small amounts of foodingredients are placed directly on theskin, with an adhesive, for one totwo days. Then, a specialist evaluateswhether or not there has been adelayed reaction to the substance.Dr. Wahn considers patch testing tobe useful, “but not to the extentthat it is considered a gold standardfor all food allergies,” he adds.

An experienced allergist will alsoexamine the context of a suspectedfood allergy, such as how the patientis feeling and any concurrent healthconditions such as immune dysfunc-tion. A negative IgE blood test doesnot always mean that you do nothave a food allergy, as a positive testdoes not necessarily mean that youhave a food allergy. “You have tocorrelate the positive test to theclinical exam or status of how thepatient is doing in real life,” Dr. Arshademphasizes. A positive test mightindicate a need for clinical challenges.Lack of a positive test might result inan allergist challenging the patientwith the food that he or she seemsto be allergic to, to reproduce anadverse reaction in a controlledsetting. Then the allergist will watchclosely to see if there is resolutionof the symptoms by eliminatingthe offending ingredient from thediet. This is called an eliminationchallenge.

Food Allergy TestingIf individuals suspect that they

have food allergies, they shouldcontact a disease-specific organizationand locate a physician that has

experience diagnosing and treatingallergies (see Resources). Only aqualified specialist can attach thecorrect meaning to the test results.Self-diagnosing food allergieswithout proper guidance can leadto poor eating habits or mislead anindividual to overlook a significantmedical problem (see Can You SayEosinophilic?).

Allergies and PregnancyAt the American Academy of

Allergy, Asthma and Immunology(AAAAI) 2007 Annual Meeting,Drs. Arshad and Wahn explainedthat they have not found clear evi-dence that allergen avoidance duringpregnancy is useful. In fact, avoidanceof certain foods during pregnancyhas potential to compromise themother’s diet. This does not meanthat avoiding allergic foods does notdelay allergies in her baby. There isevidence showing that the immunesystem may be negatively affectedby exposure to certain allergensbefore birth. Until more is known,however, these scientists agree thatit may not be practical to restrict thediet of a mother during pregnancy.

Allergies and BreastfeedingIt is not realistic to say that breast-

feeding is magic and prevents foodallergies. “If there were a clear effectof breastfeeding on allergies, therewould be no debate among scientists.Still, irrespective of food allergy,nursing is an outstanding source ofnutrients,” Dr. Arshad says. Althoughlarge-scale literature reviews andstudies show a slight protectiveeffect of breastfeeding for allergyprevention, Dr. Arshad calls attentionto the fact that ”not a single studyon prevention of allergies and exclusive

breastfeeding has been for morethan six months.” The question ofhow long breastfeeding remains atall protective is unanswered.

PreventionIf the child is at high risk of devel-

oping an allergy (high risk meaningthat at least one or more parentsor siblings has atopic disease or aconfirmed food allergy), then avoidingcertain food ingredients can improveoutcomes. Scientists report somebenefits in preventing atopic dermatitisand food allergy by eliminating cow’smilk, nuts and eggs, and sometimeswheat and tree nuts. The problem,however, is that restricting such abroad array of ingredients whilekeeping a balanced diet can betricky. Dr. Wahn hesitates to givegeneral recommendations. “In certaincases, if a mom observes a problemafter nursing, then you can confirmcases where [food allergy] is plausibleand make diet recommendations,”but “a recommendation for a whole

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group is not appropriate.” The risksand benefits must be considered. “Ifthere is a high risk and support from aregistered dietitian, restricting the dietmay be worthwhile,” Dr. Arshad says.

If the mother’s milk is insufficientthrough the sixth month, a child atrisk for developing food allergies willbenefit from a formula where theproteins have been broken down orhydrolyzed. In one study, babies givenextensively hydrolyzed formula showedsignificant reductions in allergicmanifestations compared to thosewho used regular cow’s milk formula.3

In most cases, however, formula is notsuperior to breast milk.

The American College of Allergy,Asthma and Immunology (ACAAI)recommends that the optimal agefor introducing new foods shouldbe at least six months. For childrenat high allergy risk, foods should beintroduced one at a time, in smallamounts, and on an appropriateschedule (e.g., 12 months of age fordairy products, 24 months for hen’s

eggs and at least 36 months forpeanuts, tree nuts, fish and seafood).It is helpful to keep a food journalso that you can see if there is apattern developing. If an allergy issuspected, consult with a qualifiedallergist and seek guidance from aregistered dietitian.

ReferencesWahn U., and Arshad S. (2007). Preventionand Natural History of Food Allergy. 2007Annual Meeting. Presented at the annualmeeting of the American Academy ofAllergy, Asthma, and Immunology (AAAAI),San Diego.

Johansson, SGO., Hourihane JO., Bousquet J.,Bruinjzeel-Koomen C., Dreborg S., HaahtelaT., et al. A revised nomenclature for allergy.Allergy, 2001;56,813-824.

von Berg A., Koletzko S., Grubl A., Filipiak-Pittroff B., Wichmann HE., Bauer CP.,Reinhardt D., Berdel D., German InfantNutritional Intervention Study Group. Theeffect of hydrolyzed cow’s milk formula forallergy prevention in the first year of life: TheGerman Infant Nutritional Intervention Study,a randomized double-blind trial. J Allergy ClinImmunol, 2003;111;467-470.

ResourcesAllergic Disorders:Promoting Best Practiceswww.theallergyreport.com/reportindex.html

American Partnership for Eosinophilic Disorderswww.apfed.org

National Institutes of Health, NationalInstitute of Allergy and InfectiousDiseases (2004). Food Allergy: AnOverview (NIH Publication No. 04-5518).www.niaid.nih.gov/ publications/pdf/foodallergy.pdf

Sicherer, S.H. (2006). The CompletePeanut Allergy Handbook: Understandingand Managing Your Child’s Food Allergies.Johns Hopkins Press.

Food Allergy and Anaphylaxis Network800-929-4040www.foodallergy.org

World Allergy Organizationwww.worldallergy.org

Find an Allergist• American Academy of Allergy,

Asthma & Immunology800-822-ASMA www.aaaai.org/physref

• American Academy of Pediatrics800-433-9016 www.aap.org/referral

• American College of Allergy,Asthma & Immunology 800-842-7777www.acaai.org/LocateAllergist

3 The Journal of Allergy and Clinical Immunology, 2003.