Update on Food Allergies: 2010

William Parker, MDHead, Division of Allergy and ImmunologyDayton ChildrensUpdate on Food Allergies: 2011

1ObjectivesDefinitions and statisticsKnow the current recommendations regarding immunizations in children with egg allergyFood allergies in the school settingBe familiar with the latest information regarding prevention and treatment of food allergyKey issues in the latest practice parameters for management of food allergy

Food-induced allergic disordersIgE dependentDisorderKey featuresTypical ageCommon foodsNatural courseUrticaria and angioedemaIngestion/skin contact, acute 20%, chronic 2% Children > adultsPrimarily major allergensDepends on food

Oral allergy syndromePruritus, mild edema of oral cavityAdults/older children>youngRaw fruits and vegetables, cooked toleratedVaried, may fluctuate with pollen seasonRhinitis and asthmaRarely isolated or sole symptom unless inhaledInfant /child > adult unless occupationalMajor allergens ; wheat, egg and seafood occupationDepends on foodAnaphylaxisRapidly progressive, multiple organ systemsAnyAny but peanut, tree nuts, shrimpfish, milk, eggDepends on foodFood-associated exercise-induced anaphylaxisTriggered only if food followed by exerciseOlder children and adultsWheat, shellfish and celery most describedPresumed persistentFood-induced allergic disordersIgE associated/cell-mediatedDisorderKey featuresPathologyTypical ageCommon foodsNatural courseAtopicDermatitisAssociated with food in 35% of children with moderate to severe rashMight relate to homing of food-responsive T cells to the skinInfant > child > adultMajor allergens, especially egg and milkTypically resolvesEosinophilicesophagitis, enteropathySymptoms vary with site/degree of eosinophilic inflammationEsophageal: dysphagia and painEotaxin and IL-5AnyMultipleLikely persistentFood-induced allergic disordersCell-mediatedDisorderKey featuresPathologyTypical ageCommon foodsNatural courseDietary protein enterocolitisChronic : emesis, diarrhea, poor growth, lethargyRe-exposure: emesis, diarrhea, hypotension (15%) 2 hrs laterIncreased TNF-alpha response, decreased response to TGF-betaInfantsMilk, soy, rice, oat, wheatUsually resolvesDietary protein proctitisMucus-laden, bloody stoolsEosinophilic inflammationInfantsMilk, including through breast feedingUsually resolves

Average hospital discharges per year of children with any diagnosis related to food allergyDiagnosing food allergyHistoryWhat symptomsQuantity and how preparedTime between ingestion and symptomsSimilar instances or tolerance in pastOther factors necessary (e.g., exercise)How long since the last reactionWhat foodA few foods account for about 90% of reactions

Prevalence of Food AllergyFoodinfant/childadultMilk2.5% 0.3%Egg1.5% 0.2%Peanut1% 0.6%Tree nuts0.5% 0.6%Wheat/soy0.4% 0.3%Fish0.1% 0.4%Shellfish0.1% 2%Sesame0.1% 0.1%Overall5% 3% to 4%

Food allergens-Cows milkMost common food allergy in young childrenCasein fraction 80% of proteinsWhey fraction 20%Lactoglobulins, bovine Igs and albuminCasein proteins are most immunogenicLactoglobulins and BSA in whey also important>90% will react to goat/sheep milkAbout 10% react to beef

Food allergens-chicken eggMost common IgE-mediated food allergyEgg white contains 23 different proteinsovomucoid, ovalbumin, ovotransferinOvomucoid is responsible for most reactions and has a unique structure70% of egg allergic children can tolerate extensively heated/baked productsBread, cakes, cookies

Vaccines in egg-allergic childrenVaccineACIPRed BookPIMMR/MMRVMay be usedMay be usedUse with caution, cites AAPInfluenzaConsult a physicianContraindicatedContraindicatedRabiesUse with cautionNo recommendationUse with cautionYellow feverContraindicatedContraindicatedProtocols givenVaccines in egg-allergic childrenFluMist has a very low ovalbumin contentNo pediatric data and effect of respiratory route unclearFluarix and Fluvirin have low ovalbumin contentNo data on FluLaval or AgrifluAffluria very lowNot indicated below age 9Fluzone has the highestOnly product approved for ages 6-23 monthsAmount still relatively lowVaccines in egg-allergic childrenSkin testing not universally recognized as helpfulProspective and retrospective studies-reactions rareRabies vaccine Imovax not made in chick embryro2-dose approach becoming popular10% of dose followed by 30 minute observation, then 90%Recent EP recommendation stated insufficient evidence to make broad recommendations, but felt that current ACIP, AAP Red Book, and PI recommendations may be too conservativeHow should you vaccinate the egg-allergic child?Skip the immunizationUse the 2 dose methodGive 10% of doseWait 30 minutes, give the remainder of vaccineUse the same brand product for booster if possibleSame lot is not necessaryYou should be prepared for anaphylaxis unlikleyOrRefer to an allergistFood allergens-peanutWhich of the following foods should be avoided by patients allergic to peanut?a. Mike-Sells potato chipsb. Penn Station french friesc. Chick-fil-A productsd. all of the abovee. none of the above

Food allergens-peanutMost common pediatric food allergy above age 4Peanut butter patented in 1865, hydrogenated oils added in 1922, first brand SkippyAt room temp has no vapor phase containing proteinRefined/commercial peanut oil safe, pressed oils retain some allergenicityCross-reactivity to other beans 5%

Food Allergens-Tree nutsWalnuts34%Cashew20%Almond15%Pecan9%Pistachio7%HazelnutBrazil nut90% NPV)Increasing SPT wheal size is correlated with increasing likelihood of allergy, not severityTesting with fresh food preparation helpful for fruits and vegetables

Diagnosing food allergiesFood-specific IgE antibodiesSeveral available assaysIncreasingly higher values correlate with likelihood of reaction but not severityExceedingly high values at diagnosis may reflect poor prognosis for outgrowing allergyMean level for 5 yo at which 50% react (kUa/L)Milk 2Egg 2 Peanut 5Diagnosing food allergiesFood-specific IgE antibodiesPositive Predictive ValuesNegative Predictive ValueFoodkUa/LPPVEgg infants