Food Allergy Flashcards

1
Q

Cross reactivity between peanut and tree nuts

A

33%

Some guidelines say 25-50%

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2
Q

What is the likelihood of peanut allergy in a twin sibling

A

64%

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3
Q

What is the increased risk if a parent or sibling has peanut allergy

A

7 fold

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4
Q

Which child has increased allergy risk

A

First child (decreasing birth order)

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5
Q

Name the 4 animal proteins

A
  1. Tropomyosins - crustacean and mollusks
  2. Parvalbumins/E-F hand proteins - vertebrae fish and frogs
  3. Caseins - milk
  4. Minor families - ovomucoid, oligosaccarides, transferrins, serpins, lipocalins.
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6
Q

Name the 4 plant proteins

A
  1. Prolamin- seeds, tree nuts, legumes
  2. Cupin - seed storage globulin in legumes, nuts and seeds
  3. Bet v 1 - Apple, pear, stone fruit, celery, carrot, soybean, peanut
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7
Q

Cross reactive milk with cows milk

A

Sheep and goat

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8
Q

Cross reactive foods with latex

A

Banana, avocado, chestnut, kiwi, potatoe, green pepper

The risk of reactions to kiwi, banana or avocado in Latex allergic people is 11%

The risk of latex allergy amount kiwi-banana- avocado allergic people is 35%

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9
Q

What percentage of beef allergic children reactive to cows milk?

A

75%

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10
Q

Name your differential for food allergies

A
  1. Immune mediated - IgE, FPIES, EGE, atopic dermatitis
  2. None immune - metabolic (lactose intolerance), toxic (scromboid), undefined (Sulfites)
  3. Other - Frey’s syndrome (auriculotemporal syndrome causing flush in facial nerve distribution), gustatory flushing, irritant reactions, infections
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11
Q

What is the Predictive SPT threshold for peanuts

A

Wheal size of 8 mm or greater was high predictive of having a positive food challenge (PPV 95%)

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12
Q

Which peanut component is associated with birch cross reactivity

A

Ara H8

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13
Q

Which peanut component has highest diagnostic accuracy

A

Ara H2

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14
Q

Can the results of the diagnostic test be used to predict the severity of a future allergic reaction?

A

No, the clinic should not use the result of the SPT or sIgE to whole peanut or the components to determine the severity of an allergy phenotype or to predict the severity of a future reaction

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15
Q

Name the Special circumstances for screening infants who present with food allergy

A

Special cases may be made for screening infants who present with egg allergy and severe atopic dermatitis in the first 4-6 months of life that is poorly controlled despite escalating care

NIAID did recommend strong consideration that either peanut spt or sIgE be obtained and interpreted before early peanut introduction in these infants.

There is no role for component testing for screening

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16
Q

Should children with a family history of peanut allergy in another sibling be evaluated for peanut allergy prior to being introduced?

A

Screen, but for siblings for peanuts allergy should not be routinely performed.

However, there is consideration for a role for testing when patently are overly anxious about introducing peanut and will not introduce peanut through other means

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17
Q

Are all patients with detectable ara h2 clinically allergic to peanuts?

A

No. Detectable isolated sensitization to ara h2 is not diagnostic for peanut allergy, and a diagnosis can only be made where the individual is sensitized in the context of a known or suspected reaction after eating peanut

18
Q

Does component testing predict severity

A

No. No test including components has good sensitivity or specificity to indicate the severity of symptoms of a future reaction.

19
Q

When should components be ordered?

A

The role of component testing is evolving and it is unclear how and when these tests should be used.

Ara h2 compared to peanut SPT does have higher specificity, however there is a knowledge gap on whether this should be the first test

20
Q

95% PPV for egg testing

A

7 mm

SIgE >7

21
Q

95% PPV for cows milk testing

A

> /= 8 mm

SIgE >15
Or >5 if age <1

22
Q

95% PPV for peanut testing

A

Spt >/= 8 mm

SIgE >14

23
Q

95% PPV for fish

A

SIgE >/= 20

24
Q

Natural course of milk, egg, wheat and soy

A

40% by age 8 for milk, 80% by age 16

68% egg allergy resolved by age 16

25
Q

Risk factor for death

A
  1. Underlying asthma
  2. Delayed epinephrine
  3. Symptom denial
  4. Teens
26
Q

Predictors of future tolerance

A
  1. Lower early SIgE
  2. Reduction in SIgE over time
  3. Reduction in spt wheal size
  4. Lower atopic dermatitis severity
  5. Decreased igE epitope diversity and lower igE binding affinity
27
Q

6 ways to prevent food allergy

A
  1. Do not restrict maternal diet in pregnancy or lactation
  2. For patients at risk for developing food allergy use partially or extensive hydrolyzed formulas if they are not breast fed
  3. Encourage breast feeding for 4-6 months
  4. Do not introduce soldiers until 4-6 months
  5. Do not routinely recommend probiotics or prebiotic
  6. Do not try and prevent food allergy but substituting with soy formula/milk
28
Q

Name 8 resources for families with food allergy

A
  1. CSACI
  2. AAAAI
  3. ACAAI
  4. WAO
  5. CAAIF
  6. Food allergy network canada
  7. food allergy and anaphylaxis alliance
  8. allergy and asthma information association
29
Q

mechanism of flushing with alcohol

A
  1. etoh causes vasodilation of blood vessels in the skin due to alcohol and its metabolite acetylaldehyde
  2. niacin contains nicotinic acid which leads to flushing bc of increase in prostaglandin which is a potent vasodilator
30
Q

risk factors for food allergy

A
  1. first degree relative with food allergy
  2. decreasing birth order (first child greatest risk)
  3. born in autumn or winter
  4. severe eczema and egg allergy linked to peanut sensitization
31
Q

RFs for death in food allergy

A
  1. severe uncontrolled asthma
  2. symptom denial/ previous severe reaction
  3. adolescents and young adults
  4. increased PAF
32
Q

what sIge egg cut off would stop you from a baked challenge?

A

sIgE of 11

33
Q

what is the sensitizing agent in alpha gal

A

lone star tick aka amblyomma americanum

34
Q

what is heiner syndrome?

A
  • food induce pulmonary hemosiderosis
  • most often associated with a non IgE mediated hypersensitivity to milk
  • IgG abs to cows milk are seen and needed for dx
  • presented with recurrent pneumonia, infiltrates, hemorrhages and GI blood loss
35
Q

CI to OFC

A
  • High likelihood of reacting to the food based on history, skin testing, or sIgE
  • Recent reaction in the past 6-12 months
  • Relatively contraindicated in patients with high risk of severe anaphylaxis
  • Recent convincing reaction in the past 6-12 months
  • Unstable asthma
  • Conditions that may affect resuscitation – CV disease, β-blocker use, difficult vascular access
  • Food is frequently implicated in fatal and near fatal anaphylaxis
  • Peanuts, tree nuts, fish, shellfish, seeds
36
Q

How to oral vaccines work?

A

Oral viral vaccines may work by infecting dendritic cells in the gut and stimulate a strong innate immune response that promotes T and B cell activation

37
Q

Two types of immunoassays

A

Two main types:

  1. Particle methods
    - Precipitation of immune complexes (electrophoresis)
    - Measurement of light scattering by immune complexes in solution (turbidimetry and nephelometry)
  2. Label methods
    - Uses label on antigen or antibody to identify complex formation
38
Q

what is gel electrophoresis

A
  • SPEP, Cryoglobulins, Quantitative immunoglobulins
  • Separates molecules based on their size and charge
  • Proteins are cleaved and loaded into wells in a gel
  • An electric current is passed through the chamber and proteins move towards the positive cathode
  • Separate out by weight and charge
39
Q

what is nephlemetry

A
  • Measures light scatter from serum and compares to amount of scatter from known mixtures
  • Used to determine concentration of individual serum proteins (e.g. hemoglobin, haptoglobin, complement, CRP, RF)
40
Q

most common foods in EIA

A

wheat and celery