1. Food Allergy Update Thomas Flaim, M.D.

2. Prevalence of Food Allergy Prevalence rate is 6% in children < 3 years of age; 4% in adults Prevalence rate is 6% in children < 3 years of age; 4% in adults Atopic children have higher prevalence Atopic children have higher prevalence Most common are milk (infants), egg (toddler), and peanut (school age) Most common are milk (infants), egg (toddler), and peanut (school age) 35% of children with moderate to severe atopic dermatitis have food allergy 35% of children with moderate to severe atopic dermatitis have food allergy

3. Epidemiology of Food Allergy 30,000 food-induced anaphylactic reactions/year in U.S. 30,000 food-induced anaphylactic reactions/year in U.S. 2000 hospitalizations/year in U.S. 2000 hospitalizations/year in U.S. 200 deaths/year in U.S. 200 deaths/year in U.S.

4. Effects of Early Nutritional Interventions on the Development of Atopic Disease No protective effect of a maternal exclusion diet during pregnancy No protective effect of a maternal exclusion diet during pregnancy Modest decrease in risk of atopic dermatitis and milk allergy with exclusive breastfeeding for 4 months in high risk infants Modest decrease in risk of atopic dermatitis and milk allergy with exclusive breastfeeding for 4 months in high risk infants Insufficient data for preventing and/or delaying food allergy with exclusive breastfeeding Insufficient data for preventing and/or delaying food allergy with exclusive breastfeeding For infants after 4-6 months of age, there are insufficient data to support a protective effect of any dietary intervention for the development of atopic disease For infants after 4-6 months of age, there are insufficient data to support a protective effect of any dietary intervention for the development of atopic disease Pediatrics 2008;121;183-191.

5. Natural History of Food Allergy Outgrown by age: Outgrown by age: –Milk – 20% (4 years); 40% (8 years); 60% (12 years); 80% (16 years) –Egg – 10% (4 years); 40% (8 years); 65% (12 years); 80% (16 years) –Peanut – 20% –Tree nuts – 10%

6. Fatality due to Food Allergy Peanut/nut most common cause Peanut/nut most common cause Milk responsible for 10% Milk responsible for 10% Risk factors include: Risk factors include: –Delayed use of Epinephrine –Asthma –Adolescent/young adult

7. IgE-Mediated Food Hypersensitivity Type I hypersensitivity reaction Type I hypersensitivity reaction Symptoms within minutes to 2 hours after ingestion Symptoms within minutes to 2 hours after ingestion Skin prick testing Skin prick testing –positive results - 50% tolerate foods –negative results – negative predictive accuracy of >95% In vitro allergen-specific testing In vitro allergen-specific testing –similar to skin prick testing

8. IgE-Mediated Food Hypersensitivity Double-blind placebo-controlled food challenge (DBPCFC) is “gold standard” for establishing diagnosis Double-blind placebo-controlled food challenge (DBPCFC) is “gold standard” for establishing diagnosis Conducted in clinic or hospital setting Conducted in clinic or hospital setting May perform every 1-2 days May perform every 1-2 days

9. Peanut Allergy Prevalence of 1% Prevalence of 1% Rate has doubled in past decade Rate has doubled in past decade Severity of clinical reactions does not correlate with serum peanut-specific IgE results Severity of clinical reactions does not correlate with serum peanut-specific IgE results Coallergy with legumes is 5% and tree nuts 25-50% Coallergy with legumes is 5% and tree nuts 25-50%

10. Peanut Allergy Labeling laws now require declaration of peanut proteins Labeling laws now require declaration of peanut proteins “may contain peanut” and “made in a factory that processes peanut” “may contain peanut” and “made in a factory that processes peanut” Casual contact through touch or inhalation generally not a problem Casual contact through touch or inhalation generally not a problem

11. Peanut Allergy 20% will outgrow, must be confirmed with oral challenge 20% will outgrow, must be confirmed with oral challenge 8% have recurrence but these patients did not incorporate peanut into diet 8% have recurrence but these patients did not incorporate peanut into diet 7% of younger siblings will have peanut allergy 7% of younger siblings will have peanut allergy

12. Peanut Allergy Treatment Avoidance Avoidance Emergency epinephrine available Emergency epinephrine available Anti-IgE therapy (1/2 to 9 peanuts tolerated) Anti-IgE therapy (1/2 to 9 peanuts tolerated) Sublingual or oral immunotherapy Sublingual or oral immunotherapy Chinese herbal medicine Chinese herbal medicine Immunotherapy (plasmid, peptide etc) Immunotherapy (plasmid, peptide etc)

13. Milk Allergy 2.5% of newborn infants experience hypersensitivity reactions <1 year of age 2.5% of newborn infants experience hypersensitivity reactions <1 year of age 60% are IgE-mediated; 50% then develop other food allergies 60% are IgE-mediated; 50% then develop other food allergies Most with non-IgE-mediated reactions ‘outgrow’ by 3 years of life Most with non-IgE-mediated reactions ‘outgrow’ by 3 years of life Coallergy – beef in 10% of patients Coallergy – beef in 10% of patients

14. Egg Allergy 70% tolerate extensively heated egg in baked goods 70% tolerate extensively heated egg in baked goods 20% will develop peanut allergy 20% will develop peanut allergy

15. Tree Nut Allergy Most common: Most common: –Walnuts – 34% –Cashews – 20% –Almonds – 15% –Pecans – 9% –Pistachio – 7%

16. Fish Allergy Allergen more susceptible to manipulation eg. Canned tuna, salmon Allergen more susceptible to manipulation eg. Canned tuna, salmon Allergens can become aerosolized Allergens can become aerosolized allergy to multiple fishes is common allergy to multiple fishes is common

17. Shellfish Allergy Mollusks – snails, clams, oysters, scallops, squids, octopus, mussels Mollusks – snails, clams, oysters, scallops, squids, octopus, mussels Crustacea – shrimp, lobsters, crabs, prawns, crawfish Crustacea – shrimp, lobsters, crabs, prawns, crawfish Allergens can become aerosolized Allergens can become aerosolized Considerable cross-reactivity among crustacea Considerable cross-reactivity among crustacea

18. Treatment Injectable epinephrine available Injectable epinephrine available –<50 lbs- Epipen Jr. (.15 mg) SQ –>50 lbs – Epipen (.30 mg) SQ Avoidance Avoidance Immunotherapy (SQ, sublingual and oral) under investigation Immunotherapy (SQ, sublingual and oral) under investigation Omalizumab (anti-IgE) Omalizumab (anti-IgE) Chinese herbal remedies Chinese herbal remedies

19. Non-IgE-Mediated Food Hypersensitivity Type IV – cell-mediated Type IV – cell-mediated –Eosinophilic esophagitis and gastroenteritis –Atopic dermatitis –Celiac disease

20. Non-IgE-Mediated Food Hypersensitivity Food protein-induced enterocolitis syndrome Food protein-induced enterocolitis syndrome Food protein-induced colitis Food protein-induced colitis Dietary protein-induced enteropathy Dietary protein-induced enteropathy Symptoms include vomiting, diarrhea Symptoms include vomiting, diarrhea

21. Non-IgE-Mediated Food Hypersensitivity Potential complications include bloody diarrhea, FTT, malabsorption, dehydration Potential complications include bloody diarrhea, FTT, malabsorption, dehydration Etiologic agents – milk and/or soy based formula, breast milk Etiologic agents – milk and/or soy based formula, breast milk Treatment is avoidance and use of elemental formula Treatment is avoidance and use of elemental formula Resolution in majority of infants by 2 years of age Resolution in majority of infants by 2 years of age

22. Class 2 Allergenic Proteins Consequence of an allergic sensitization to inhalant allergens Consequence of an allergic sensitization to inhalant allergens “Latex-fruit” allergy (banana, avocado, chestnut, kiwi, fig) “Latex-fruit” allergy (banana, avocado, chestnut, kiwi, fig) Oral Allergy Syndrome Oral Allergy Syndrome

23. Oral Allergy Syndrome Symptoms confined to oropharynx and rarely involve other target organs Symptoms confined to oropharynx and rarely involve other target organs Cooked foods tolerated Cooked foods tolerated Birch pollen Birch pollen –Apple, pear, peach, cherry, apricot, plum, carrot, celery, potato, hazelnut Ragweed Ragweed –melons

24. Conclusions Make a correct diagnosis (food allergy cripples)! Make a correct diagnosis (food allergy cripples)! Treatment is avoidance and availability of injectable epinephrine although we should have therapy in next 10-20 years Treatment is avoidance and availability of injectable epinephrine although we should have therapy in next 10-20 years