Update on eczema and food allergy Associate Professor Rohan Ameratunga

1. Update on eczema and food allergy Associate Professor Rohan Ameratunga

2. Update on food allergy • Food allergen update incl cross-reactivity • Epidemiology • Case history: diagnosis including testing • Type 1 reactions incl anaphylaxis • Prevention of food allergy • FA studies in NZ

3. Adverse Reactions to Food Toxic (eg. Ciguatera)Non Toxic ImmuneNon Immune (Food Allergy) (Food Intolerance) IgE Non-IgEEnzymatic Chemical Pharmacologic Unknown Food Aversion (eg eczema) (eg celiac) (lactase) (eg.salicylate) (histamine)

4. Pathogenesis IgENon-IgE Anaphylaxis/angioedema Gastrointestinal anaphylaxis Oral Allergy Syndrome Eczema Allergic Eosinophilic Esophagitis, Gastritis & Gastroenteritis Dietary protein colitis, proctitis and enteropathy [Celiac Disease]

5. Food allergens • When food allergy is confirmed, it usually proves to be restricted to 1 or 2 foods • Young children: milk, egg, peanut, tree nuts, soy, andwheat account for about 90% of cases • Adolescents and adults: peanut, fish, shellfish, and tree nuts account for about 85% • Cultural variation eg rice in Japan, increasing sesame allergy in NZ and Australia • Newly recognized allergens incl Anisakis, Lupin

6. Multiple food allergy • Food contamination • Cross reactivity • Food chemical sensitivity • True multiple food allergy

7. Food cross-reactivity

8. Epidemiology of food allergy • 20% to 25% of American public report being allergic to one or another food - most such beliefs are incorrect • Careful studies, with oral challenge, demonstrate food allergy in 2% to 4.0% of the population • Prevalence higher in children 6%-8% • 2.3% adolescents in Isle of Wight (0.9% peanut) • This is consistent with data from around the world. • No studies conducted in NZ- see later in this talk • ? Increase in food allergy over the last 20 years • Patterns of food allergy changing with migration and changes in diet

9. The prevalence of food allergy: A meta-analysis Rona et al JACI Sep 2007 • Papers selected from the literature • Categorised according to methodology • Cochrane methodology • Stringent criteria for inclusion • Divided according to age group • Unselected population papers, not enriched populations such as clinic patients

10. The changing face of food hypersensitivity in an Asian community Chiang et al Clin Exp Allergy 2007 • Very little data on food allergy in Asia • Different diets • Ethnic makeup Chinese, Indian, Malays, Eurasian • Melting pot: Rapidly changing lifestyle • Increasing westernisation of diet • Previous data indicates Chinese have major issues with fish and shellfish

11. The changing face of food hypersensitivity in an Asian community • Study centre Kerdang Kerbau children's Hospital outpatient centre • Methods prospective data on children referred with suspected food allergy • Spt data collected 2003-2006 • Inclusion compatible history and + spt • Other allergies documented eczema and allergic rhinitis, asthma

12. The changing face of food hypersensitivity in an Asian community • Spt positive results • Egg 40% • Shellfish 39% • Peanuts 27% • Fish 13% • Cow’s milk 12% • Sesame 9% • Wheat 6% • Soy 3%

13. The changing face of food hypersensitivity in an Asian community • Food introduction • Egg 8.6mo • Fish 6.6mo • Shellfish 12.2mo • Fish introduced at the same time or earlier as eggs in 83% of children

14. Update on food allergy • Epidemiology • Food allergen update incl cross-reactivity • Case history: diagnosis including testing • Type 1 reactions incl anaphylaxis • Prevention of food allergy • FA studies in NZ

15. Case history (type 1 reaction) • Emma aged 18 months • Chronic eczema • Ate peanut butter • Within 5 minutes developed hives, angioedema and breathing difficulty • Treated appropriately-recovery

16. Case history (type 1 reaction) • Managing anaphylaxis • Useful diagnostic procedures • Long term management plan • What is her long-term prognosis? • How common is this problem? • Is there any specific treatment? • What is known about FA in NZ? • Can this problem be prevented?

17. Pathogenesis

18. Spectrum of IgE mediated food allergy • Anaphylaxis, urticaria, angioedema: classical anaphylactic reaction • Gastrointestinal anaphylaxis: no cutaneous symptoms • Food-dependent exercise induced anaphylaxis • Oral allergy syndrome: include itching of the mouth, and swelling of the tongues and lips - associated with eating FRESH apple, carrots, hazelnut, bananas, melons • Eczema: Up to 50% of young children with eczema may have a food allergy trigger • Milk-allergy has been associated with nausea, vomiting, diarrhea, bloating, early satiety, reflux, esophagitis, gastritis, malabsoption, abdominal pain, and bloody stool

19. Treatment of anaphylaxis • Keep patient lying flat- risk of sudden death • Elevate legs to assist venous return • Risk of late reactions • Patients should be admitted/observed for at least 6 hours • Serum tryptase 1-2 h after reaction • Fill out ACC form

20. Adrenaline • Dose Adults 0.3-0.5 mg Children 0.01 ml/kg 1:1000 ie 10 µg/Kg • EPI-PEN 0.3 mg • EPI-PEN Jr 0.15mg (8-20Kg) • Syringe, needle and vial of adrenaline • Adrenaline Inhaler- potential problems • IV adrenaline only for cardiac arrest • Twinject- new device

21. Individuals at increased risk • Patients with asthma • Antihypertensives esp  blockers • MAO inhibitors • Cardiovascular disease • Pregnancy

22. Diagnostic procedures • Short term elimination diets • Food challenges • Skin testing • RAST testing • Food patch testing • Novel methods incl peptide microarrays

23. Diagnostic elimination diets • Suspected food to be eliminated for 2-3wks • If no response, consider more stringent diet • Should be supervised paediatric dietician • Foods gradually re-introduced • Trial of Neocate

24. Skin testing

25. Skin testing

26. RAST testing Foodcut-off sensitivity specificity Egg6.0 U/ml 61% 92% Milk15 U/ml 51% 98% Peanut15.0 U/ml 73% 92% Fish 19.5 U/ml 40% 99% Wheat > 100 U/ml PPV 60% Soy > 100 U/ml PPV < 50%

27. Determinants of the severity of a reaction • Sensitivity (food specific IgE) • Amount of food consumed • Digestion: use of antacids • Absorption rate (slowed by charcoal) • Co-factors (aspirin, exercise, alcohol) • Sensitivity can increase with subsequent exposures (memory)

28. Update on food allergy • Epidemiology • Food allergen update incl cross-reactivity • Diagnosis including testing • Type 1 reactions incl anaphylaxis • Prevention of food allergy • FA studies in NZ

29. Food allergy management plan • Education re foods and avoidance-dietician • Written action plan • MEDIC-ALERT emblem-velcro • Public Health nurses to visit school/daycare • Anaphylaxis video (Allergy NZ) • Follow up RAST testing 6-12 monthly • Food challenge if RAST becomes negative

30. Self-injectable adrenaline

31. Self-injectable adrenaline

32. Self-injectable adrenaline

33. Anaphylaxis action plan

35. Fatalities from food allergy • Food allergy is the leading cause of anaphylaxis requiring ER visits - with twice the incidence, and three times the mortality, of anaphylactic reaction to bee stings • Approx. 125 people die in USA each year • In Canada 8 people died from food in 1998 • In Australia 5 recent deaths • ? In NZ 1-2 deaths every 1-2 yrs

36. Risk factors for fatal reactions • Peanut or tree nut allergy • Previous severe food reaction • Asthmatic- most deaths result from asthma • Adolescent / teen-age • Adrenaline – unavailable or not used early • No Emergency “action plan” • Allergy Un-awareness / Un-educated • “Healthy degree” of anxiety is required

37. Natural History of food allergy • Milk and egg allergy improve over time • Once remission occurs, no recurrence • Taste may be an issue • Recent data suggesting milk allergy may persist into adolescence • 20-30% of peanut allergy remits: serial RASTs • Up to 9% of children with tree nut allergy improve

38. Peanut allergy • Commonest cause for food allergy death • In Isle of Wight prevalence of sensitization up from 1.3 to 3.2% from ’89 to ’95 • Similar results from random telephone survey in US • 75% of reactions occur on 1st known exposure • Sensitization could occur in utero, breast-feeding or skin contact (creams with peanut oil) • Either isolated allergy or associated with multiple other food and aero allergies • Use of peptide arrays • Recombinant RAST tests

39. Recent studies on peanut allergy • ?Risk of sensitization by soy formula • ?Risk of sensitization with topical creams eg Caster oil • Small risk with airborne peanut allergen eg aircraft • Boiled peanuts less allergenic than roasted peanuts • Europeans and Americans may be reacting to different peanut allergens • As little as 100ug can cause reactions eg kissing • Reduction in accidental exposure • Concern about management of peanut anaphylaxis

40. Recent studies on peanut allergy • Up to 20-30% of peanut allergic children remit • Remission more likely with lower peanut IgE levels • Higher risk of recurrence with infrequent peanut ingestion • Cross-reactivity with other nuts (or co-sensitization) • Chinese herbal preparation: protection against murine peanut anaphylaxis

41. Anti-IgE therapy • Recent study with TNX 901 showed anti-IgE therapy can markedly improve peanut allergy • Threshold doses increased from 1/2 peanut to 8 peanuts • Lawsuit- project discontinued • Currently phase 2 study of Omalizumab (Xolair) Leung et al NEJM 2004

42. Recent studies on peanut allergy • Peanut desensitisation • Two studies Cambridge and Durham NC • ?

43. Update on food allergy • Epidemiology • Food allergen update incl cross-reactivity • Case history: diagnosis including testing • Type 1 reactions incl anaphylaxis • Prevention of food allergy • FA studies in NZ

44. The changing epidemiology of food allergy Proposed food allergy studies in NZ

45. Questions • What is the burden of food allergy? • Can food allergy be prevented? • What services are utilised by patients • What are the gaps in services • What is the response of Gov’t agencies? • Are there any unusual food allergies in NZ? • What is the natural history of food allergy?

46. Agencies involved in food allergy • Ministry of health • ARPHS • DHBNZ • Ministry of Education • PHARMAC • MEDSAFE • ACC • Ministry of Trade and Industry • FSANZ • NZFSA • IGA

47. Lack of food allergy data in New Zealand • Currently little data specific to food allergy • May be similar to overseas?? • However ethnic makeup different • Ethnic makeup rapidly changing • Role of genetics • Feeding practices may be different • Available foods are different eg shellfish

48. Lack of food allergy Research in New Zealand • Lack of data is hindering medical services • No public food allergy service in south Island for children • Epipens unfunded

49. Lack of food allergy Research in New Zealand • Ad hoc approach in schools • Issues with preschools

50. Lack of food allergy Research in New Zealand • Risk management issues for food industry and hospitality industry • Important for food export industry • Public not aware of the problem • Impact on quality of life not appreciated