Food Allergy I William Reisacher, MD FACS FAAOA Department of Otorhinolaryngology Weill Cornell Medical College
History of Food Allergy Old Testament - Hebrews place dietary restrictions in order to prevent disease. 3000 B.C. Cutaneous reactions caused by foods are recorded in China. Hippocrates Observation that milk could cause gastric disturbance as well as urticaria. 1
History of Food Allergy 1906 Von Pirquet introduces the concept of allergy. 2 1932 Herbert Rinkel describes a second, delayed, type of food allergy and introduces the oral food challenge. 3 1958 Carleton Lee develops the technique of provocative food testing and neutralization therapy. 4
Adverse reactions to foods Food hypersensitivity immunologic reactions Food intolerance non-immunologic reactions So what is food allergy?
Food Intolerance Anaphylactoid reactions non-immune release of chemical mediators and histamine by tomatoes and strawberries or ingested in foods like spoiled fish. Digestive enzyme deficiencies lactase Malabsorption celiac disease Toxic reactions MSG, staph toxin Pharmacologic reactions chemicals in foods have a drug-like effect
Immunology of Food Reactions First requirement is penetration of immunologic particles through tissue barriers in the body Antigenically intact food macromolecules can be transported across the mature mammalian gut Leaky gut in children and elderly IgA deficiency leads to increased antigen absorption Foods are subjected to multiple external forces prior to exposure to the body
Food Hypersensitivity IgE-mediated Gel and Coombs Type I reaction Comprise 5-10% of hypersensitivity Usually an immediate reaction Neither dose nor frequency dependent Associated with eczema, asthma, urticaria, oral allergy syndrome, GI syndrome and anaphylaxis.
Food Hypersensitivity Non-IgE-mediated Gel and Coombs Types II IV reactions Represents 90-95% of hypersensitivities IgG and T cell mediated Reactions may be immediate or delayed Dose and frequency dependent Symptoms tend to fluctuate Believed to cause disease at multiple target organs by deposition of immune complexes Elevated CIC found in allergy, asthma and Meniere s disease
IgE Anaphylaxis Manifestations of Food Oral allergy syndrome Allergic rhinitis Acute asthma Mixed IgE and non-ige Hypersensitivity Eosinophilic esophagitis, gastritis, enteritis Acute/chronic urticaria, angioedema, atopic dermatitis Chronic asthma
Type of Hypersensitivity in Food Allergy Kekki OM, et al. 1997 113 infants with atopic eczema 54 were positive for milk allergy via double blinded oral milk challenge test Prick and patch testing Type I prick+ patch- Type II/III prick- patch- Type IV prickpatch+ Mixed prick+ patch+ 8 (15%) 19 (35%) 14 (26%) 13 (24%)
Fate of Immune Complexes Antigen excess: small complexes containing IgG or IgM which deposit in tissues, causing injury from complement fixation and local inflammation. Equality or antibody excess: large complexes that are cleared rapidly, causing little or no tissue damage.
The Cycle of Sensitization High levels Of Antibody Omission for 4 days Stage 2 Hyperacute Sensitization (oral challenge) Stage 3 Active Sensitization Stage 4 Foods avoided Continuously (Symptoms decrease) Latent sensitization Stage 5 Masked Sensitization Stage 1 Active Sensitization Stage 9 Foods used regularly In normal amounts (Symptoms increase) Latent Sensitization Stage 8 Tolerance with Avoidance Stage 6 Tolerance with Rare use of foods Stage 7 Low levels Of Antibody
Demographics of Food Allergy Estimated to affect up to 6-8% of the pediatric population. 5 Eight foods account for over 90% of allergic reaction in children: milk, eggs, peanuts, tree nuts, fish, shellfish, soy and wheat. Food allergies highest in the first 2 years of life. Among children >2 undergoing ENT procedures, food allergy prevalence was 17.7% 6 Nsouli et al. evaluated 104 children with recurrent SOM 78% met the criteria for food allergy. 7
Peanut Allergy Overall, present in 1% of the population Ara h 1, Ara h 2 and Ara h 3 Twin studies suggest genetic linkage 8 7% risk to siblings of peanut allergic child 9 5% risk of reaction to other legumes Only 20% will outgrow peanut allergy Studies support restricting peanut intake during pregnancy and lactation 10 Oral desensitization remains controversial
Food Cross-Reactivity Closely related food species Pecans and walnuts Soy and peanut Wheat and barley/rye Unrelated food species Mollusks and crustaceans Food-inhalant from related pollen Rye pollen with rye or wheat flour Food-inhalant from unrelated pollen Birch trees with carrots, apples Ragweed with watermelon and canteloupe
Food Allergy on the rise? NCHS Data Brief, October 2008 From 1997-2007, reported food allergies in children increased by 18% Children with food allergy are 2-4 X more likely to have asthma or allergies than children without. Increased incidence vs. increased awareness Overestimation of food allergy Globalization of diet Variations in food preparation.
References 1 Chobot R. Pediatric allergy. New York: McGraw-Hill, 1951. 2 Von Pirquet C. Allergie. Much Med Wochenschr 1906;53:1457. 3 Rinkel HJ. Food allergy. J Kans Med Soc 1936;37:177-184. 4 Lee CH. A new test for detection of food allergies, pollen and mold incompatibilities. Buchanan Co Med Bull 1961;25:9. 5 Sampson HA, Ho DG. Relationship between foodspecific IgE concentrations and the risk of positive food challenges in children and adolescents. J Allergy Clin Immunol 1997;100:444-51.
References 6 Bhombal S et al. Prevalence of elevated total IgE and food allergies in a consecutive series of ENT pediatric patients. Oto Head Neck Surg 2006;134:578-580. 7 Nsouli TM, Nsouli SM, LInde RE et al. Role of food allergy in serous otitis media. Ann Allergy 1994;73:215-9. 8 Sicherer SH, Furlong TJ, Maes HH et al. Genetics of peanut allergy: A twin study. J Allergy Clin Immunol 2000;106:53-6. 9 Hourihane JO, Dean TP, Warner JO et al. Peanut allergy in relation to heredity, maternal diet, and other atopic diseases. BMJ 1996;313:518-521. 10 Sicherer SH. The impact of maternal diets during breastfeeding on the prevention of food allergy. Current opinion in Allergy and Clinical Immunology 2002;2:207-210.