2. Food Allergies: Diagnosis & Management
2010 NIAID Guidelines

3. Overview
2010 Guidelines
Introduce all potentially allergenic foods around 4-6 months of age, vague risk stratification given
Do not restrict maternal diet during pregnancy or lactation for the purpose of preventing FA or AD
Diagnose FA based on detailed medical history and targeted confirmatory testing
Avoid known allergen ingestion and treat reactions
Monitor for tolerance
No specific immunotherapy recommendations
2017 Addendum: Prevention of peanut allergy by risk stratified introduction strategies
Low and moderate risk, introduce peanuts around 6 months, goal of 3 feedings (6-7 g total) / week
High risk individuals (Egg allergy or severe atopic dermatitis), test first, then introduce if able, otherwise avoid
What is not known yet
Risk stratification strategies for prevention of other food allergies
Specific criteria for immunotherapy interventions (peanut and tree nut)

4. Prevalence of food allergies – Grossly OVER REPORTED
However, studies on the incidence, prevalence, and epidemiology of food allergies, especially in the US are lacking.

5. Food Allergy: Symptoms
Erythema
Pruritis
Hives
Angioedema
Vomiting / Reflux
Strider
Cough
Wheezing
Syncope
Anaphylactic Shock
Severity of reaction ~
Amount ingested
Form (cooked, raw, processed)
Co-ingestion of other foods
Age of patient
Degree of sensitization
Rapidity of absorption
Empty stomach
Alcohol or NSAID ingestion
Exercise AD
Asthma*
Severity of prior reaction is not predictive

6. Diagnosing Food Allergies
Screen for reactions to specific foods, particularly if on more than one occasion and/or a young child
6% of children < age 5 have food allergy
Milk, Eggs & Peanut common under age 5
Peanuts, tree nuts and shellfish more common in adolescents & adults
Detailed history to identify trigger and other contributing factors
Confirm with testing as 50-95% of reported reactions are not true food allergies
Recommended diagnostic testing
Oral challenge = gold standard
Skin Prick testing
High sensitivity and negative predictive values, low positive predictive power compared to oral challenge
sIGe to allergen (95% predictive values per allergen)
SPT and sIGE together can increase the predictive values
Discouraged testing
Pan allergen testing by SPT or sIGE
Total IGE
Intradermal or patch testing (systemic rxns, little incremental benefit)

7. Natural Course & Monitoring Food Allergies
Changes in SPT response are not well defined, may stay positive even in the presence of tolerance, wheal shrinkage is thought to correlate with tolerance
Drop in sIGE levels over time
Oral tolerance is gold standard
No data driven recommendations re: frequency of testing, general guidance:
Milk, egg soy, wheat – annually
Peanut, tree nuts, shell fish every 2-3 years
Skip if had recent reaction

8. LikELihood of Outgrowing various Food Allergies
Not as quick as I thought
Limited data – generally from follow-up at single clinics, no community based data
Generally based on oral tolerance from accidental ingestion and/or defined sIGE level (based on allergen) and then passing oral challenge
Egg:
Roughly 10% by age 4, 25% by age 6, half by age 8 and 80% by age 12
Milk:
80% by age 5
Wheat:
25% by age 4, half by age 8 and 65% by age 12
Soy:
25% by age 4, half by age 6, 70% by age 10
Peanut
Tree Nut

9. Treating Food Allergies
Avoid
Urgent & Emergent Treatment of reaction
Oral challenges once levels drop < 95% predicted values
Immunotherapy options
2010 Guidelines not recommended for anyone
New studies: / practice is changing

10. SUMMARY: So what do we do?
Screen for risk of food allergies (severe eczema, or egg allergy and other soft calls – FH: FA)
Encourage early introduction of food allergens based on risk level / test if child is high risk for food allergy
Screen for observed food reactions
Confirm suspected food allergies with diagnostic testing
Treat allergic reactions
Monitor for reduction in sensitivity
Refer if patient if diagnostic uncertainty, patient is a potential candidate for immunotherapy, situation is complicated by multiple allergies, other chronic process (FTT, refractory eczema, severe allergic disease) or parents would like specialist care

11. Summary: What Not to do
Recommend deferred introduction of food allergens across the board
Pan test for food allergens
Test for cross antigens
Restrict multiple food allergens without referring to allergist

12. Answering Parent questions
Why have the recommendations changed so much in the past decade regarding food allergies and introduction of foods?
But the WHO says to exclusively breast fed until 6 months of age…
Why do we need to do any testing when I’m telling you that they had an allergic reaction to ”x”?
If my child has “x” allergy, are they more likely to have other food allergies? Should we test them for other allergies? Can we just test them for everything?
Will my child outgrow their “x” allergy? When? How will I know if they outgrow it? Do we really need to get repeat testing?