Hugh A' Sampson, MD

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Hugh A. Sampson, MD
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How to Manage the Child with Life-threatening
Peanut Allergy

• Hugh A. Sampson, M.D.
• Professor of Pediatric Immunobiology
• Jaffe Food Allergy Institute
• Mount Sinai School of Medicine
• New York, NY

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Prevalence of Peanut Allergy

• Overall U.S. prevalence 0.6 or 1.7 million
• American children lt 5 yrs 0.8 - 80 were
  breast fed gt 90 of mothers recalled ingesting
  peanut - first known exposure median 12
  months - first known reaction median 14
  months

Sicherer et al JACI 1999 103559-62 JACI
20031121203-07 Sicherer et al JACI 2001
108128-132 Bock et al JACI 2001 107191-93.
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Peanut Allergy is Increasing

• Isle of Wight, UK, Birth cohort, to age 3-4 yrs
• 1989 data 1 positive PST/0.5 allergic
  reaction
• 1995 data 3.3 positive PST (p 0.001) / 1
  reported reaction (1.5 estimated reactive
  (Grundy et al JACI 2002)

Prevalence of peanut allergy doubled in
children lt 5 yrs
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Why is Food Allergy Increasing?

• Bottom line We dont know !
• Theories - hygiene hypothesis -
  Westernized diet - ready accessibility
  and early introduction of allergenic foods
  - processing / cooking methods e.g. dry
  roasted vs boiled peanuts - change from
  primarily n 3- to n 6- PUFA in fetal infant
  diet - Vitamin D supplementation

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CASE A 4 y/o old boy had an anaphylactic
reaction to a cookie at age 2 yrs but no tests
were performed at the time presumptive
diagnosis of peanut allergy. Serum
peanut-specific IgE is now undetectable.
Previous Severe Reaction

• What is the next best step
• Add peanut to the diet, probably never allergic
  test now for other possible triggers (e.g., nuts)
• Perform oral food challenge under physician
  supervision
• Repeat peanut-specific IgE level to confirm
  result
• PST to peanut

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Confirming Peanut Allergy

• History typical IgE-mediated symptoms - young
  infants with atopic dermatitis may not
  demonstrate acute symptoms
• Skin testing prick or puncture - PST
  variability extract, method, technician, etc.
• Quantitative IgE Cap System FEIA or UniCAP
  - some commercial labs extrapolate values
• Oral food challenges open, SBFC, DBPCFC -
  must exclude patient observer bias - risk of
  severe reaction

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History of Peanut Reactions

• 1st reaction median 14 mos mean 18 mos -
  1st known exposure to peanut in 75
• Target organs affected skin 89
  respiratory 42 GI
  26 cardiovascular 4 - half affected
  more than one target organ
• 76 were treated with medication - one-third
  treated by medical personnel
• In young children, increasing severity with
  increasing reactions, but unpredictable

Sicherer et al. JACI 2001 108128-32.
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PST Wheal Size Reactivity

• 64 of 140 children evaluated for peanut allergy
  had a PST - 18 of the 64 had positive
  peanut challenge

• All children with challenges had PSTs
  gt 5 mm
• 9 of 17 children with PST gt 10 mm had a
  negative challenge

Pucar et al. Clin Exp Allergy 2001 3140-46.
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Quantitative Peanut-IgE

• Atopic Dermatitis (Sampson JACI 1997100444)
• Concentration (CAP-RAST in kU/L) may be
  predictive in context of atopic dermatitis
• 196 patients, mean age 5.2 years, 100 atopic
  dermatitis
• Concentration gt 15 kU/L, 95 positive predictive
  value

• Acute Reactions (Sampson JACI 2001)
• Prospective study Not selected for AD
  (50)

Probability

• Confirmed by Roberts et al JACI 2005

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Outgrowing Peanut Allergy

• 20 of children lt 2 yrs will outgrow
  peanut allergy
• Patients reacting to peanut beyond 5 yrs of
  age rarely outgrow peanut allergy
• Monitoring peanut-specific IgE levels Peanut
  IgE (kU/L) Passing Challenge lt
  5 55 lt 2 63 lt0.35 73
  Fleischer et al. JACI 2003 112183-189.
• 10 will re-develop clinical reactivity

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Natural History of Peanut Allergy
103 Children (lt5 kU/L)
55 with history of adverse reaction
48 avoiding w/o history of reaction
Busse et al. NEJM 2002 3471535-36
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Who Should be Re-challenged?

• Weigh history, PN-specific IgE and PST results
• Predicting passage of peanut challenge HX lt
  0.35 0.36 - lt 2 2 4.9 gt5 kU/L
  76 44 40 0 ? 88
  71 33 77 Perry et al JACI
  2004 114144-149.
• PST gt 8mm and PN-IgE lt 2 kU/L lt 40 pass
• More likely to pass if PN-IgE never gt 5 kU/L, PST
  lt 3 mm no reaction in past 3 yrs, isolated
  allergy
• No correlation with severity of 1st reaction

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Your patient has peanut allergywhat about beans,
tree nuts or other foods?
Question

• The most accurate statement is
• He/she is very likely to test positive to
  beans, but probably will not react when eating
  them
• Tree nuts do not share many allergenic proteins
  with peanut, but there is a higher risk for
  allergy to them for you anyway
• One and two above
• None of the above

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Peanut and Legume Cross-reactivity
Barnett JACI 1987 Bernhisel-Broadbent JACI
89 Sampson J Pediatr 1985 Burks J Pediatr
1998 Bock JACI 1989 Bernhisel-Broadbent JACI 89
PST
PST
113 AD
165 AD
32 PNA
41 Legume
0
20
40
60
Risk

• Caution?
• Lupine (Moneret-Vautrin JACI 1999)
• Lentil (Pascual JACI 1999)

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Peanut Allergy and Nuts
Hourihane 1996
Sicherer 1998
Ewan 1996
Sicherer 2003

Bock 1989
0
10
20
30
40
50
60
Percent Peanut and Tree Nut Allergic
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Case 2½ y/o with severe AD and rhinitis has
never eaten much peanut, spits it out hates
the smell, but no known allergic reaction.
Infant with Distaste for Peanut

• The most reasonable approach
• The history indicates no reaction (just
  distaste) and a test to peanut is likely to be
  falsely positive so advise no change in
  approach
• Indicate there is a significant risk for a
  reaction to peanut and advise further testing
• Indicate the risk for a reaction is very low,
  but further testing is prudent

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Identifying High Risk Patients

• No correlation with - size of prick skin test
  - quantity of peanut-specific IgE
• History of previous severe reactions
• Asthmatics especially poorly controlled
• Teenagers and adults
• multiple food allergies
• High allergenic IgE epitope diversity

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Acute Management of Anaphylactic Reaction

• Emergency treatment plans in writing FAAN
  website www.foodallergy.org
• Access to self-Injectable epinephrine
• Antihistamines liquid cetirazine or
  diphenhydramine
• Medic Alert tag
• Go to medical facility (911, ER)

• No role for oral steroid
• or activated charcoal

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Emergency Action Plan

• FAAN food allergy form www.foodallergy.org
• Medical ID

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Who Should get Epinephrine?

• Virtually all patients with confirmed peanut
  allergy
• Severity is unpredictable - does not correlate
  with PST size, PN-specific IgE level, or
  lack of previous severe reaction - more often
  severe in patients with asthma in those
  who had a previous severe reaction - tend to
  increase in severity with increasing age
• Only 20 of patients dying of a fatal food
  allergic reaction experienced a severe
  reaction previously

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Chronic Management Avoidance

• Obvious sources
• Hidden ingredients
• Cross contamination
• Non-ingestion contact

• Peanut oil - Processed (distilled) peanut
  oil usually ok
• - Cold pressed extruded gourmet oil NOT
  ok
• ? Avoid packaged in a plant with peanut
  products or may contain peanut
• High risk places (school, restaurants)

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The Peanut Allergy Registry Where Reactions
Occurred
Percent Reported By Location
Sicherer et al. 2001 JACI 108128-132.
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Establishment/Part of Meal
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Mistakes When Ordering for Allergic Patient
(n106)

• Only 45 of families warned establishment
• When warned and verified, various mistakes
• server errors, contamination
• In 78 of episodes, establishment knew PN/TN
  was an ingredient
• 50 of these, PN/TN were hidden (sauces)
• 22 due to cross-contamination
• Shared utensils, serving equipment, cooking
  equipment

Remaining mistakes (n21) buffet, contact
Furlong TJ et al. JACI 2001 108867-70.
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Recommendations

• Patient education
• Risks in various settings
• Notification of restaurant personnel
• Identification of appropriate individual
• Clear communication of ALLERGY
• Consider Chef cards
• Preparation for accidents
• Restaurants/food establishment education
• Seriousness of food allergy
• Cross-contamination

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PAR Database School Reaction Severity/Treatment

• 90 received medication
• - 86 antihistamines
• - 28 epinephrine

Sicherer et al. J Pediatr. 2001138560-565.
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Peanuts on Airplanes

• Peanut allergen measurable in airplane filters
  (Jones JACI 199697423)
• Clinical reactions (Sicherer, JACI
  1999104186-189)
• 62 of 3,704 Peanut/Tree Nut Registry
• 42 confirmed peanut-35(4 suspect), tree
  nut-7
• Peanut (mean age- 2 years range 0.75-50 yrs)
• ingestion (14), skin (7), inhalation (14)
• Severity increased ingestiongtinhalationgtskin
• 79 treated, 5 received epinephrine
• Only 33 reported reaction to airlines

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Inhalation Reactions on Airlines

• 10/14 subjects reported peanut as cause
• Peanut served to gt25 passengers
• Reactions moderate (2), mild (5), minimal (3)
• 4/14 subjects suspected peanut
• Severe, 20 minutes after boarding, peanuts
  not yet served
• Mild, 20 minutes, not served
• Severe reaction, 40 minutes after serving
• Minimal reaction, one minute after served

Sicherer, JACI 1999104186-189
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Question of Exposure

• A 7 y/o PN-allergic child is rushed to an ER with
  severe wheezing hives. The child had just
  finished eating lunch in the cafeteria.

• The most likely cause of the reaction is
• Peanut in her lunch sent from home
• Smell of peanut butter from sandwich of child
  sitting next to her
• Peanut butter on hands from touching peanut
  residue on table
• Child touching her arm with PN residue on hands

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Relevance of Casual Contact

• Casual skin contact or inhalation of peanut
  (PN) butter fumes is reported to cause allergic
  reactions in highly sensitive PN- allergic
  children (Tan, Ann Allergy 2001)
• Common settings
• Schools (Sicherer, J Pediatr 2001)
• Commercial airlines (Sicherer, JACI 1999)
• Kissing (Hallett, NEJM 346(23)1833-4, 2002)
• These reactions are based primarily upon
  self-report, and not verified (ingestion is
  typically not excluded)

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Peanut Exposure

• Casual contact study to peanut butter
  (Simonte 2003 112180-182)
• 30 highly allergic children
• Touch X 1 min, sniff X 10 minutes
• No reactions (beyond site of touch)
• School Lunch (Banerjee et al JACI 2004 abst)
• 14 Canadian schools peanut-free lunches
• Bag inspections-100 were peanut-free (50
  agreed to allow inspection)
• Peanut-free homes (Grundy et al, JACI 2004 abst)
• Rate of accidental ingestions higher (0.15/yr
  vs 0.10/yr) in peanut-free home families
  most accidents outside home

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Peanut Residue

• Hand cleaning
• No peanut after water/soaps or wipes
• Plain water/antibacterial liquid left residue
  3/10 hands
• Table tops
• Common cleaners-fine
• Dishwashing liquid left residue 2/10
• School locations (6 schools)
• 1/13 water fountains (130 ng)
• 0/22 desks, 0/33 cafeteria tables
• Airborne
• None detected

Perry et al JACI 2004 113973-76
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Ingestion Thresholds

• Caveats in studies
• Patient selection, challenge approaches,
  symptoms, matrix of challenge, protein vs. peanut
• Various results
• Subjective-0.1 mg, objective- 2 mg (Hourihane
  1997)
• Median 3 mg (lowest 0.1 mg) (Wensing 2002)
• Average 200 mg (Leung 2003)
• In general
• 1/50th to 1/100th of a peanut in some, rarely
  severe
• ½ peanut for average person with significant
  allergy to induce treatment-requiring symptoms

Peanut butter- 20-25 protein 1 peanut 200 mg
protein
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Future Immunotherapies

• Oral immunotherapy OIT and SLIT
• Anti-IgE immunotherapy
• Engineered recombinant protein
• Chinese Herbal medications

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Lessons from Fatal Reactions
Need to educate

• PMDs to prescribe emergency plan
  epinephrine
• patients to avoid desserts snacks outside
  of home, recognize symptoms, carry and use
  epinephrine
• school personnel serving staff about food
  allergy allergen contamination
• restaurant personnel serving staff about
  food allergy allergen contamination
• EMTs about use of epinephrine