Associate Professor Rohan Ameratunga

Transcription

1 Associate Professor Rohan Ameratunga Adult and Paediatric Clinical Immunologist and Allergist Auckland 9:25-9:45 Preventing Food Allergy

2 Update on Food allergy Associate Professor Rohan Ameratunga Food allergies I was on an elimination diet

3 Update on food allergy Introduction Epidemiology Current management of food allergy Prospects for food allergy prevention ASCIA recommendations

4 Disclosures Honorarium from Nutricia Nutricia has given an unrestricted educational grants for FA research Previous funding from Fonterra for FA research

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

6 Food allergy history Detailed history critical in food allergy If a patient is tolerating the food in spite of a positive test- they must continue Risk of breaking tolerance If the patient is sensitized but has nor previously had the food- they may be at risk of reacting Important to consider supervised food challenges. No other safe way to determine tolerance

7 USA & UK Milk Egg Peanut Tree Nuts Seafood FRANCE Egg Peanuts Milk Mustard ITALY Milk Egg Seafood ISRAEL Milk Egg Sesame SINGAPORE Birds Nest Seafood Egg Milk AUSTRALIA Milk Egg Peanuts Sesame

8 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

9 Pilot study of Plunket Clinics in Auckland Ethnicities of participants study 2006 census NZ European 62% (60.4%) Maori 20.8% (14.3%) Chinese 9.4% (3.7%) Samoan 8.3% (3.3%) Indian 11.5% (2.7%) Cook Island 5.2% (1.5%) Tongan 5.2% (1.3%) Niuean 4%

10 Determinants of the severity of a reaction Sensitivity (levels of food specific IgE) Amount of food consumed Digestion: use of antacids Absorption rate (slowed by charcoal) Co-factors (virus, aspirin, exercise, alcohol) Sensitivity may or may not increase with subsequent exposures (memory) Allergenicity: Hyperallergenic foods

11 Self-injectable adrenaline

12 Anaphylaxis action plan

13 Non-anaphylaxis action plan

14

15 Peanut allergy

16 Food allergen avoidance/ Long-term elimination diets Accurate diagnosis is critical Often food challenges are neededotherwise nutritional risk of multiple food elimination Pediatric dietician assessment essential Reading food labels Allergy New Zealand incl alerts

17 Nutritional risks of long-term elimination diets Allergen Milk Egg Soy Wheat Peanut Vitamin and Minerals Vitamin A, vitamin D, riboflavin, pantothenic acid, vitamin B 12, calcium, & phosphorus Vitamin B12, riboflavin, pantothenic acid, biotin, & selenium Thiamin, riboflavin, pyridoxine, folate, calcium, phosphorus, magnesium, iron, & zinc Thiamin, riboflavin, niacin, iron, & folate if fortified Vitamin E, niacin, magnesium, manganese, & chromium

18 Preventing FA: The 5 D s Diet Dogs Dribble/ gut flora Vitamin D Dry skin Offspring from migrants acquire a higher risk

19 Avoidance of peanuts 1998 UK 2000 USA Avoidance of early peanut introduction Increasing prevalence of peanut allergy Rescinded 2008

20 Early introduction of peanuts in Israel Major difference between UK and Israeli Jewish children Bamba in Israel 10x prevalence in UK Jewish children

21 LEAP STUDY

22 LEAP STUDY 640 children enrolled 4-11 months High risk: egg allergy and/or eczema Skin tested and randomised for peanut avoidance or consumption to 60months 530 had negative skin tests 13.7% of avoidance group had pna by 60mo 1.3% of peanut consumption children had pna by 60mo.

23 LEAP STUDY

24 LEAP STUDY

25 LEAP STUDY- caveats 98/640 had positive skin tests to peanuts Not advised unless tested and challenged 18 in pn consumption group reacted to baseline challenge or developed pna during the 60months How long will tolerance persist in children consuming peanuts? See LEAP ON study Cannot draw any conclusions about other allergenic foods Cannot draw any conclusions about low risk infants. Early introduction of egg in a previous study was abandoned because of severe reactions.

26 LEAP ON STUDY Follow up study of LEAP study patients Primary question of whether the reduced risk of PNA was sustained if patients stopped eating peanuts. Patients invited to stop eating peanuts for a year Then retested or challenged.

27 LEAP ON STUDY

28 EAT/Breastfeeding study

29 EAT/ Breastfeeding study 1303 breast fed infants randomly selected from UK Randomised 3/12: given eggs, milk, wheat, fish, sesame and peanut Others usual feeding practices Results 7.1% had FA vs 5.6% intention to treat (non significant) But poor compliance in early introduction group Might not be a practical option

30 EAT/Breast feeding study

31 Those adhering to protocol-peanuts

32 EAT/Breast feeding study- egg

33 EAT/Breast feeding study: showing mean weekly consumption related to risk

34 Final conclusions-preventing food allergy Encourage breastfeeding Moisturise HA formulas probably ineffective Insufficient data on probiotics etc If a child is tolerating a food- continue! Any signs of significant eczema or suspected FA - test! Any concerns- refer for management Patients will need on going evaluation

35

36 ASCIA guidelines Family history of allergic disease in a parent or sibling (family history of allergic disease in both parents OR a parent and a sibling is associated with a further increased risk). Introduction of cow's milk or soy milk formula before 3-4 months of age (an increased risk for eczema and food allergy). Introduction of solid foods before 3-4 months of age (an increased risk for eczema and food allergy). Should use emollients.

37 ASCIA guidelines Breast feeding Where possible, breast feed your child for at least 6 months. Breast feeding provides a nutritious and balanced food source for your baby, reduces the risk of gastrointestinal tract infections and may also reduce the risk of developing allergic disease in early life. Where possible, delay the introduction of formula feeds until the child is 4-6 months of age.

38 ASCIA guidelines Partially hydrolysed formula (commonly referred to as HA' formula) are cow's milk based formulas that have been processed to break down some of the proteins. Emerging evidence suggests that partially hydrolysed formula does not have a significant protective effect against allergic disease although this remains contentious. Partially hydrolysed infant formula should not be used in infants who are already cow s milk allergic. Delay the introduction of solid foods until the child is 4-6 months of age. Thereafter, foods can be introduced, with a new food introduced every 2-3 days. Introduce one new food at a time so that any reactions can be readily identified.

39 Paediatric food allergy/ eczema clinic JHU Prof Robert Wood Prof Hugh Sampson Prof Ken Schurberth