FOOD ALLERGY

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FOOD ALLERGY

• Department of Gastro - Enterology
• Childrens Hospital No. 2

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References

• http//www.ebm-guidelines.com/
• Uptodate 2008
• Cochrane reviews
• Finnish Medical Society Duodecim. Paediatric food
  hypersensitivity and allergy. In EBM Guidelines.
  Evidence-Based Medicine Internet. Helsinki,
  Finland Wiley Interscience. John Wiley Sons
  2008 Apr 10 Various. 13 references

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Introduction

• Food hypersensitivity food allergy food
  intolerance.
• Food allergy categorized
• IgE-mediated
• non IgE-mediated
• both mechanisms
• A skin-prick test or tests for specific
  immunoglobulin E (IgE) antibodies (RAST) in the
  serum may be used in the determination of an
  immunological mechanism.

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Introduction

• Most infants suffering from food allergy to
  nutritionally important foods (milk, cereals)
  recover at pre-school age.
• School-aged children may develop allergy to
  vegetables or fruit.

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Epidemiology

• General population 2
• Young children (lt 3 yrs) 8
  
• Young children with severe eczema 90
• Children with asthma lt 10

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Manifestations of food allergy

• 1. SKIN urticaria angioedema ? eczema
• 2. RESPIRATORY rhinitis asthma
• 3. GI TRACT diarrhea vomiting
• - eosinophilic
  gastroenteritis
• - enterocolitis
• 4. GENERAL anaphylactic shock
• 5. OTHER migraine, hyperactivity,
• sleep disturbances etc ?

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Causes of Food Allergy

• Any food can cause allergy
• In children gt 90 of acute systemic reactions to
  food (anaphylactic reactions) eggs, milk, soy,
  wheat, or peanuts.

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Foods triggering anaphylaxis in Singaporean
children (1992 1996)

• 124 children with acute anaphylaxis at NUH
• mean age (yrs)
• 1. Egg and milk 11 0.7
• 2. Birds nest 27 4.5
• 3. Chinese herbs 7 5.0
• 4. Crustacean seafood 24 11.0
• 5. Others 30 7.0

Chicken, duck, fruits (banana, rambutan),
cereals, gelatin and spices
Goh et al. Allergy 54, 1999, 78-92.
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Cow's Milk and Cereal Allergies

• Nutritionally most significant (Räsänen Ylönen,
  1992)
• Mainly seen in young children
• Prevalence 2.5 during the first two years of
  life (A review of 229 PubMed 1967 - 2001 )
• Rarely after pre-school age
• Symptoms caused by these foods usually appear in
  infancy soon after the food has been introduced
  to the child's diet.

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Allergens Related to Pollen Allergy

• Allergens
• Root vegetables potato, carrot, celery
• Fruit and other vegetables apple, pear, peach,
  kiwi fruit, plum, mango, tomato
• Spices mustard, ginger, cinnamon
• Others walnut, almond
• In most cases preparation of vegetables (cutting,
  freezing, and especially cooking) removes the
  allergenicity, the majority of persons allergic
  to pollen can eat cooked vegetables.

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Other Allergens

• Peanuts, soya, fish, shellfish, eggs, wheat,
  barley, oats, rye, buckwheat, banana, avocado
• Linseeds, sesame seeds and poppy seeds
• Mushrooms
• Alcoholic drinks
• Cereal allergens, aniseed, colouring agents,
  benzoic acid

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Diagnosis of Food Allergy

• Skin-prick and radioallergosorbent tests (RAST)
  for specific foods 85 sensitive, 30 - 60
  specific.
• ? specific IgE/blood
• Intradermal testing higher false-positive rate
  higher risk for adverse reactions ? not be used
  for the initial evaluation of food allergy.
• Atopy patch tests diagnosis of non-IgE mediated
  food allergy, not be recommended outside of
  research settings
• Most specific test to confirm the diagnosis is
  still the double-blind, placebo-controlled food
  challenge
• GOLDEN STANDARD DBPCFC

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Future immunomodulatory therapies for food allergy

• 1. Humanized monoclonal anti-IgE
• 2. Peptide immunotherapy
• 3. Immuno-stimulatory sequences
• 4. Probiotics (?) no effect on allergic
  reactions

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• Allergen immunotherapy for patients with food
  allergy, chronic urticaria, and/or angioedema is
  not recommended (National Guideline
  Clearinghouse, level B)

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Prevention

• To prevent allergies, the risk groups should be
  identified reliably, and an efficient
  preventative measure should be available (Csonka
  et al., 2000).
• Maternal antigen avoidance during lactation has
  no effect on the incidence of atopic eczema in
  the child according to one small study (Kramer
  Kakuma, 2006) D.

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Prevention

• Maternal avoidance of food allergens during
  pregnancy (third trimester) does not prevent
  atopic manifestations in the infant (Kramer
  Kakuma, 2006) C.
• All studies concerning prevention have been
  carried out in children at high risk of atopy,
  the evidence has been reviewed to be of poor
  quality (Brand, Vlieg-Boerstra, Dubois, 2007).

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Prevention

• Exclusive breast feeding for at least 4 to 6
  months is recommended, but the allergy-preventing
  effect of this is modest at best (Kramer
  Kakuma, 2002).

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Prevention

• Partially hydrolysed formulas are effective when
  breast-feeding is not available for high-risk
  infants (Baumgartner et al., 1998 Osborn Sinn,
  2003) A.

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Follow-Up

• Indications for referral to specialist care
• An infant with widespread eczema or worsening
  symptoms
• An infant with perplexing symptoms
• Failure to thrive

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Follow-Up

• In primary care
• The growth charts of a child on an elimination
  diet is monitored.
• Vaccinations
• The family is encouraged to expand and
  rationalize the diet towards a normal diet.
• The child's diet should be re-evaluated at 5
  years of age at the latest
• All elimination diets at school-age should be
  based on an established diagnosis.

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Conclusion

• Primary prevention food allergen avoidance
  important
• Breast milk is best

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Thank you for your attention !