Dietetic Practice in the Management of Adverse Reactions to Foods

1. Dietetic Practice in the Management of Adverse Reactions to Foods Clinical Practice Workshops 2009-2010

2. Diagnosis of Adverse Reactions to Foods Signs, Symptoms, and Differential Diagnosis

3. The Medical Paradigm • Signs and Symptoms suggest the disease condition • Tests are used to provide a definitive diagnosis and suggest a probable cause • Diagnosis determines the treatment • Treatment typically consists of: • Medications • Surgery • Other appropriate measures

4. Food Allergy and the Medical Paradigm • Food does not cause allergy • The immunological or physiological response to the food is the cause of symptoms • The same food can trigger entirely different symptoms in different individuals, and sometimes different symptoms in the same individual • “One cause, one disease” does not apply

5. Food Allergy and the Medical Paradigm • A specific test will not identify the cause • Most people can eat the allergenic food without symptoms • Food allergy treatment involves medications to control the symptoms • There is no way to stop the allergic reaction once it has started • Prevention involves avoidance of the allergenic food

6. Signs and Symptoms of Food Sensitivities Symptoms vary from individual to individual Sometimes symptoms vary in presentation and severity in the same individual on different occasions • Symptoms appear in all organ systems but tend to be most obvious in: • Skin: • Flushing • Hives • Angioedema (swelling especially of facial areas: lips, throat, tongue) • Itching • Eczema • Rash

7. Signs and Symptoms of Food Sensitivities • Digestive tract: • Stomach ache • Abdominal bloating • Diarrhea • Alternating diarrhea and constipation • Nausea • Vomiting • Heart burn and reflux • Differential diagnosis: Food sensitivity not indicated • Weight loss • Blood in stool

8. Signs and Symptoms of Food Sensitivities • Respiratory tract: • Stuffy nose • Runny nose • Itchy, watery eyes • Difficulty breathing, speaking, or swallowing • Throat tightening • Chest tightening

9. Signs and Symptoms of Food Sensitivities Other organ systems: • Drop in blood pressure • Rapid heart rate • Anxiety; sense of doom • Faintness • Paleness • Loss of consciousness

10. Signs and Symptoms • Anaphylaxis • Involves all organ systems • In rare cases can proceed to cardiovascular collapse • Has the very rare potential to proceed to fatal anaphylactic shock • Management always involves administration of injectable adrenalin (epinephrine) and immediate transportation to emergency medical facilities

11. Epipen and Twinject • How to use injectable epinephrine (adrenalin) • http://foodallergies.about.com/od/emergencytreatment/ht/autoinjector.htm • Free training kits available: • Epipen 1-877-374-7361 • Twinject 1-877-894-6532

12. Signs and Symptoms • In babies and children: • Digestive tract distress: • Abdominal pain • Spitting up or vomiting • Diarrhea • May be blood in stool • Irritability • Difficulty sleeping • Failure to thrive • Eczema • Other rashes

13. Diagnosis of Food Hypersensitivity • The symptoms that suggest food sensitivity may actually be caused by many different medical conditions • Frequently the idea of food hypersensitivity is suggested when all other causes for the person’s symptoms have been ruled out • Before food sensitivities are considered, ensure that other causes for the symptoms have been ruled out by appropriate medical investigations

14. Differential Diagnosis • For example: • Celiac disease: high levels of: • anti-tissue transglutaminase antibodies (tTGA) • anti-endomysium antibodies (EMA) • Intestinal infection: stool analysis for: • ova and parasites for parasitic infestations • Clostridium difficile • Other pathogens or potential pathogens • Inborn errors of metabolism

15. Potential Causes of Adverse Reactions to Foods • IgE mediated food hypersensitivity • Food allergy and anaphylaxis • Oral allergy syndrome (OAS) • Latex-food syndrome • Non-IgE mediated food hypersensitivity • Food protein enteropathies • Eosinophilic esophagitis • Eosinophilic gastroenteritis • Eosinophilic proctocolitis • Celiac disease

16. Potential Causes of Adverse Reactions to Foods • Non-immunologically mediated food sensitivity (food intolerances) • Lactose intolerance • Sucrose intolerance • Fructose intolerance • Histamine intolerance • Sulphite sensitivity • Nickel sensitivity • Sensitivity to food additives: • Tartrazine and other azo dyes • Benzoates

17. Treatment of Adverse Reactions to Food • Whatever the physiological basis of the reaction, dietetic management is the same: • Accurate identification of the food components responsible • Avoidance of the offending food ingredient • Provision of a diet that provides complete balanced nutrition from alternative sources • Recognition of the development of tolerance

18. Exercise 1 : Signs and Symptoms Questionnaire

19. IDENTIFYING THE CULPRITS Tests

20. Primary RequirementAccurate Identification of the Culprit Foods • There is a lack of definitive diagnostic tests for food allergies, food intolerances, and other adverse reactions to foods • Skin tests and blood tests detect indicators of probable sensitization to an allergen – usually IgE • They often do not identify the offending food because the mere presence of antibody to the food does not predict the response when the food is consumed

21. TESTS FOR FOOD ALLERGY AND INTOLERANCE • Skin tests: scratch; prick; intradermal • Positive response indicated by wheal and flare reaction in the skin • Size usually measured 0 - 4+ • Indicate release of inflammatory mediators, especially histamine, from skin mast cells Skin mast cells release inflammatory mediators in response to stimuli different from those that trigger mediator release from mast cells in other body tissues - especially the digestive tract

22. Value of Skin Tests in Practice • Positive predictive accuracy of skin tests rarely exceeds 50% (estimates 30% - 60%) • Many practitioners rate them lower • Negative tests for some highly allergenic foods thought to have close to 100% predictive accuracy • Such foods include: • egg  milk • fish  wheat • tree nuts  peanut

23. Value of Skin Tests in Practice • Negative skin tests do not rule out the possibility of non-IgE-mediated hypersensitivity reactions • Do not rule out food intolerances (non-immune-mediated reactions) • “Skin tests for food allergy are especially unreliable because of the large number of false positive and false negative reactions” _________ David 1993

24. Reasons for False Positive Skin Tests • Degranulation of skin mast cells by stimuli that do not degranulate mast cells in the digestive tract • Differences in the form in which the food is applied to the skin compared to that which encounters immune cells in the digestive tract • antigens in fruits and vegetables change when cooked • allergen may be derived from an unstable food extract • digestive processes can unmask antigens

25. False Negative Skin Tests • Children younger than 2-3 years are more likely to have a negative skin test and positive food challenge than adults • Adverse reaction is not mediated by IgE • Commercial allergen may contain no material that the immune system can recognize

26. Blood Tests for Food Allergy • RAST, FAST, ELISA and others • Test for the presence of anti-food antibodies • Detect anti-food IgE • The mere presence of the antibody does not indicate clinical significance • Positive tests often do not correlate well with observed reactions when the food is eaten

27. Value of Allergy Tests in Practice • A key message is that a positive allergy test result (skin or blood) indicates only the presence of allergen specific IgE (called sensitization) • It does not necessarily mean clinical allergy (ie, allergic symptoms with exposure). • It is important for this reason that the allergy evaluation be based on the patient's history and directed by a health care professional with understanding of allergy ____________ Cox et al 2008

28. Use of the Information Use the information obtained from evaluation of the patient to determine: • which allergy diagnostic tests to order • how to interpret the allergy diagnostic test results • how to use the information obtained from the allergy evaluation to develop an appropriate therapeutic treatment plan.

29. Which Tests Should I Order? • Allergen-specific IgE tests are carried out by a variety of approved methods in Canada • Provincial medical plans usually pay for 5 tests per person per year • Order “food mixes” for the initial five tests • If any are positive the lab will test individual foods within the groups at no additional charge • Do not advise patient to avoid all the foods in the positive mix without further investigation

30. Examples of Blood Tests for allergen-specific IgE • Phadia UniCAP System • This assay system can measure levels of allergen-specific IgE as low as 0.1 kU/L • The clinical relevance of results in the range of 0.1-0.35 kU/L warrants study.

31. Which Tests Should I Order? • Examples of food mixes: • Legume mix (peanuts, soy, beans, lentils) • Vegetable mix • Fruits mix • Grains (includes wheat) • Nut and seed mix • Animal origin foods (milk, egg, meats) • Fish mix • Mollusks and shellfish

32. Example: Grains

33. Legumes

34. Mollusks

35. Milk & constituents

36. Testing for IgG4 against foods • Testing for IgG4 against foods is not recommended as a diagnostic tool: EAACI Task Force Report. • Serological tests for immunoglobulin G4 (IgG4) against foods are persistently promoted for the diagnosis of food-induced hypersensitivity • Many patients believe that their symptoms are related to food ingestion • Tests for food-specific IgG4 represent a growing market • Testing for blood IgG4 against different foods is performed with large-scale screening for hundreds of food items by enzyme-linked immunosorbent assay-type and radioallergosorbent-type assays in young children, adolescents and adults. ______________ Stapel et al 2008

37. Value of IgG4 Tests in Practice Many serum samples show positive IgG4 results without corresponding clinical symptoms. IgG4 against foods indicates that the person has been repeatedly exposed to food components, which are recognized as foreign proteins by the immune system Its presence should not be considered as a factor which induces hypersensitivity, but rather as an indicator for immunological tolerance, linked to the activity of regulatory T cells. ______________ Stapel et al 2008 _______________ Tomicic et al 2009 37

38. Use of IgG4 Test Results • Food-specific IgG4 does not indicate food allergy or intolerance, but rather a physiological response of the immune system after exposure to food components. • Testing of IgG4 to foods is considered as irrelevant for the laboratory work-up of food allergy or intolerance and should not be performed in case of food-related complaints. ______________ Stapel et al 2008

39. Unorthodox Tests • Many people turn to unorthodox tests when avoidance of foods positive by conventional test methods have been unsuccessful in managing their symptoms • Tests include: • Vega test (electro-acupuncture) • Biokinesiology (muscle strength) • Analysis of hair, urine, saliva • Radionics • ALCAT (lymphocyte cytotoxicity)

40. Disadvantages of Unreliable Tests • Diagnostic inaccuracy • Therapeutic failure • False diagnosis of allergy • Creation of fictitious disease entities • Failure to recognize and treat genuine disease • Inappropriate diets • Malnutrition

41. Consequences of Mismanagement of Adverse Reactions to Foods • Malnutrition; weight loss, due to extensive elimination diets • Food phobia due to fear that “the wrong food” will cause permanent damage, and in extreme cases, death • Frustration and anger with the “medical system” that is perceived as failing them • Disruption of lifestyle, social and family relationships

42. The Bottom Line • Elimination and Challenge is the only accurate method of identifying the specific foods responsible for a person’s adverse reactions • Suspect foods are eliminated from the diet for a specific period of time • Challenge is conducted by reintroducing each eliminated food individually and monitoring the person’s response

43. Identifying the Culprits Elimination and Challenge

44. Elimination and Challenge • Removal of the suspect foods from the diet, followed by reintroduction is the only way to: • identify the culprit food components • confirm the accuracy of any allergy tests • Long-term adherence to a restricted diet should not be advocated without clear identification of the culprit food components

45. Elimination and Challenge Stage 1: Exposure Diary • Record each day, for a minimum of 5-7 days: • all foods, beverages, medications, and supplements ingested • composition of compound dishes and drinks, including additives in manufactured foods • approximate quantities of each • the time of consumption

46. Exposure Diary(continued) • all symptoms experienced graded on severity: • 1 (mild); 2 (mild-moderate) • 3 (moderate) 4 (severe) • time of onset • how long they last • Record status on waking in the morning. • Was sleep disturbed during the night, and if so, was it due to specific symptoms?

47. Exercise 2: Food Record Symptoms Record

48. Increase Restrictions Symptoms Disappear Symptoms Persist Reintroduce Foods Sequentially or Double-blind Symptoms Provoked No Symptoms Diagnosis Not Confirmed Diagnosis Confirmed Food Intolerance: Clinical Diagnosis Elimination Diet: Avoid Suspect Food

49. Elimination Diet Based on: • detailed medical history • analysis of Exposure Diary • any previous allergy tests • foods suspected by the patient • Formulate diet to exclude all suspect allergens and intolerance triggers • Provide excluded nutrients from alternative sources • Duration: Usually four weeks

50. Therapeutic Diets • Certain conditions tend to be associated with specific food components • Suspect food components are those that are probable triggers or mediators of symptoms • Examples: • Eczema: highly allergenic foods • Migraine: biogenic amines • Urticaria/angioedema: histamine • Chronic diarrhea: disaccharides • Asthma: cyclo-oxygenase inhibitors; sulphites