IgE-mediated Food Allergies

Transcription

1 The image part with relationship ID rid13 was not found in the file. IgE-mediated Food Allergies Kirsi M. Järvinen-Seppo, MD, PhD Click to edit Presenter Name Dept. of Medicine, Division of Allergy, Asthma & Immunology Center for Immunology and Microbial Diseases Click to edit Presenter Title Edit fields in View>Master Slide

2 Outline Definitions Signs and Symptoms Food Allergy-Induced Diseases Prevalence and Natural History Diagnosis and Management Prevention

3 What Is Food Allergy? A food allergy is an untoward response to a food protein that involves an immunologic mechanism When the food is eaten, the immune system releases histamine and other chemicals responsible for symptoms Almost any food can cause a reaction

4 Adverse Food Reactions Toxic Non-Toxic Food poisoning Non-Immune Mediated Immune-Mediated Lactase deficiency Anorexia Anxiety IgE-Mediated Urticaria / Angioedema Anaphylaxis; Food-Dependent, Exercise-Induced Anaphylacis Immediate GI symptoms Bronchospasm; Baker s asthma Pollen food allergy syndrome Mixed Atopic dermatitis Eosinophilic gastroenteropathy Asthma Non-IgE-Mediated Enteropathy; Proctocolitis; Food Protein-Induced Enterocolitis Heiner s syndrome Dermatitis herpetiformis Celiac disease

5 Prevalence Perception by public: 20-25% Confirmed allergy (oral challenge) Adults: 1-2% Infants/Children: 6-8% (~1/4 million births) Dye / preservative allergy (rare) Peanut allergy tripled

6 Food Allergens Children 6-8% Adults 3-4% Cow s milk 2.5% Egg 1.3% Peanut 1% Soybean Wheat Tree nuts Fish Shellfish Peanut Tree nuts Fish Shellfish * Fruits and vegetables in birch-allergic adults (25-75%)

7 Symptoms of a Food-Allergic Reaction Within minutes to 2 hours after eating the food Respiratory tract: mouth tingling, itching/swelling of the mouth/throat, cough, difficulty breathing, wheezing, asthma GI tract: abdominal cramps, vomiting, diarrhea Skin hives, eczema, itchy eyes, swelling

8 Symptoms of a Food-Allergic Reaction Severe reaction -- two or more systems Drop in blood pressure Loss of consciousness Death This type of severe reaction is called Anaphylaxis

9 Anaphylaxis A severe, potentially life-threatening allergic reaction Anaphylaxis can be caused by food allergy, insect stings, medications, latex Food-associated, exercise-induced With particular food + exercise Up to 200 people die each year from food-induced anaphylaxis

10 Food-Induced Anaphylaxis Occurs if food is ingested Has been reported from inhaling allergencontaining vapors during the cooking of allergen-containing food Smelling peanut butter will not result in physical contact with an allergen Casual contacts by skin cause local hives but no systemic reaction

11 Cutaneous Manifestations of Food Allergy

12 Food Allergy in Specific Disorders Disorder Food Allergy Prevalence Anaphylaxis 35-55% Oral allergy syndrome Atopic dermatitis Urticaria Asthma Chronic rhinitis 25-75% in pollen allergic 37% in children (rare in adults) 20% in acute (rare in chronic) 5-6% in asthmatic or food allergic children Rare

13 Disorders Not Proven to be Related to Food Allergy Migraines Behavioral / Developmental disorders Arthritis Seizures Inflammatory bowel disease

14 Oral Allergy Syndrome Oral pruritus, rapid onset Usually fresh fruits and vegetables Cooked forms, no reaction Cause: crossreactive proteins pollen/food

15 Diagnosis History: symptoms, timing, reproducibility Diet details / symptom diary Specific causal food(s) Hidden ingredient(s) Identify general mechanism Allergy vs intolerance Suspect IgE-mediated Prick skin tests, RAST Suspect non-ige-mediated Consider biopsy of gut, skin

16 Diagnosis Positive prick test Indicates presence of IgE antibody NOT clinical reactivity (~50% false positive) Unproven/experimental tests (useless) Provocation/neutralization, cytotoxic tests, applied kinesiology, hair analysis, IgG4 Elimination diets (1 to 6 weeks) Eliminate suspected food(s), or Prescribe limited eat only diet, or Elemental diet Oral challenge testing (MD supervised, ER meds available)

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18 Management

19 Management of Food Allergy Avoidance Nutritional management Recognition of symptoms Management of acute allergic reactions An emergency plan of action: ۰what symptoms to look for ۰what medications to use ۰medication dosage instructions ۰where will medications be kept ۰what teachers, students should do

20 Treatment of Food Allergic Reactions Oral antihistamines for milder symptoms Intramuscular epinephrine Self-injectable device readily available EpiPen Jr / Adrenaclick / Auvi-Q Jr 0.15 mg Epi Pen / Adrenaclick / Auvi-Q 0.3 mg Follow up in the ED or call hour observation period Emergency plan in writing - Schools, spouses, caregivers, mature sibs / friends Emergency identification bracelet

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22 Treatment: Dietary Elimination Hidden ingredients (peanut in sauces or egg rolls) Labeling issues ( spices, changes, errors) Code words ( Natural flavor may be milk) Advisory labeling is voluntary and unregulated (shared equipment, manufactured in a facility) Seeking assistance Registered dietitian: (

23 FALCPA Food Allergen Labeling and Consumer Protection Act of 2004 Any ingredient derived from the 8 major food allergens (milk, soy, wheat, egg, peanut, tree nut, fish, shellfish) must be listed by it s common rather than scientific name For example, if casein is an ingredient in the product, the word milk must also be on the product label

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25 New Therapies Oral Immunotherapy Peptide Immunotherapy Engineered recombinant proteins Traditional Chinese Medications Tolerance of extensively heated allergens (egg, milk) Recombinant anti-ige antibody

26 Prognosis Depends on food & type of food allergy Majority of milk, egg, wheat, soy allergy outgrow Declining/low levels of specific-ige predictive Allergy to peanut, nuts, seafood typically persist Non-IgE-mediated GI allergy Infant forms resolve 1-3 years Toddler / adult forms more persistent

27 Summary History and physical paramount IgE & non-ige mediated conditions Diagnosis by allergy testing, elimination and challenge Avoidance/education/preparation for emergencies are current therapies Periodic re-challenge to monitor tolerance as indicated by history, allergen, and level of food specific-ige

28 Resources FARE Food Allergy Research and Education American Academy of Allergy, Asthma and Immunology (aaaai.org) Albany Medical Center Allergy and Immunology Tel