The Rise of the IgE
Disparities exist among patients with physician-diagnosed food allergy. Which statement is true?
A. Non-Hispanic African American children are more likely to have food allergy than non-Hispanic White children.
B. Adult males are more likely to have food allergy than females.
C. Hispanic children are at greater risk of food allergy than non-Hispanic African American children.
D. Non-Hispanic White children have higher rates of food-induced anaphylaxis and ED visits.
A! Non-hispanic African American children are 40% more likely than non-Hispanic White children to have FA. Hispanic children have a 20% higher risk of FA than White children.
Other answers:
B. Rates of FA in adults: 7.8% of females, 4.6% of males
C. Wrong - see A above.
D. Black and Hispanic children have 2-3 x higher rates of food anaphylaxis and ED visits
Respiratory reactions to airborne food allergens have been reported when exposed to vapors/steam from cooking the following foods, EXCEPT:
A) Fish
B) Shellfish
C) Egg
D) Peanut
E) Garbanzo beans
D = Peanut
All other foods listed - fish, shellfish, egg, garbanzo beans - have the potential for allergen to aerosolize and cause clinical reactions
This is the culprit allergen in "Chinese Restaurant Syndrome". Reactions start 15-20 minutes after a meal, and lasts for 2 hours. Symptoms include numbness at back of neck that radiate down arms neck and back, generalized weakness, palpitations.
MSG - Monosodium Glutamate
Which of the following is a risk factor for persistence of cows milk allergy?
A) Serum cows milk-specific IgE concentration less than 50
B) History of anaphylaxis to cow's milk
C) Concurrent asthma
D) Presence of allergy to other foods
E) Reactions to baked milk
E - Reactions to baked milk.
A 6 month old exclusively breast-fed infant developed profuse, repetitive emesis, pallor and lethargy 2 hours after ingesting rice cereal. He was dehydrated and received intravenous fluids in the ED. What is the correct approach to introducting foods in this infant?
A) Rice can be reintroduced at home after the 1st birthday
B) All foods can be introduced liberally without any specific precautions
C) Rice can be introduced after 18 to 24 months of age under physician supervision
D) Delay introduction of all solid foods until after 1st birthday
E) Delay introduction of all cereal grains until 1st birthday
C - Rice can be reintroduced after 18 to 24 months of age under physician. This is an acute FPIES reaction. Recommend reintroduction q12-18 months - physician supervision in this infant because of severity of reaction.
Risk of reaction to other grains ~50%
What is the mechanism of action of omalizumab?
A) Binds to FceR1
B) Binds to FceR2
C) Binds to light chain (Fab fragment) of IgE
D) Binds to heavy chain (Fc fragment) of IgE
D - Omalizumab (xolair) binds to the Ce3 domain of the heavy chain (Fc fragment) of IgE -- see slide!
This is a MUST KNOW FOR BOARDS!
A 2 year old with anaphylaxis to nutella comes to clinic for a new patient appointment to see you. Her parents ask you about what her chances are of outgrowing her tree nut allergy. You tell them it is approximately...
A) 5%
B) 10%
C) 15%
D) 20%
B - There is a ~9% chance of a child outgrowing their tree nut allergy.
What is this were a 9 year old or 15 year old child?
Which is NOT considered an augmentation factor with increased severity of food-allergic reactions?
Exercise
Menstruation
Antacid Use
Beta Blockers
Beta Blockers
A 9 month old girl has anaphylaxis to a peanut butter cracker characterized by vomiting and hives. What is her approximate chance of outgrowing her peanut allergy?
A) 2-5%
B) 9-15%
C) 20-30%
D) 30-40%
C - Between 20% and 33% of peanut allergic children become tolerant to peanut with age.
BONUS for 100 points! What is the chance she will react to at least one tree nut allergy (as she is peanut allergic)? 10%, 20%, 30%, 40% or 50%?
Flu vaccines can safely be administered to egg allergic patients. Which 2 vaccines DO they need to avoid?
Yellow fever
Rabies
The basophil activation test (BAT) is a flow-cytometry based assay that measures basophil activation/degranulation by detection of what cell surface marker?
A) CD23
B) CD63
C) CD19
D) CD25
B = CD63
Other answer choices...
CD23 = low affinity IgE-receptor (FceRII)
CD19 = often co-expressed with CD20, major protein markers found on the surface of B cells
CD25 = alpha chain of the IL-2 receptor, highly expressed on Tregs
How do you calculate a clinically significant elevation in tryptase?
2 + 1.2 basal serum tryptase
Which environmental risk factors are linked to the development of food anaphylaxis?
A) Living in the Northern area of the US
B) Vaginal delivery at birth
C) High vitamin D levels
D) Premature birth
E) Summer season of birth
A - living in the Northern areas of the US is an established risk factor for the development of FA.
Other factors: low sunshine months (aka winter), low vitamin D, c-section birth
What percentage of MILK vs EGG allergic patients are able to tolerate extensively heated (baked) products?
A. 80% vs 75%
B. 70% vs 80%
C. 75% vs 70%
D. 65% vs 80%
C - 75% of milk allergic and 70% of egg allergic patients will tolerate baked products.
This intensely pruritic rash is characterized by:
A) increased numbers of Langerhan cells
B) IgA granule deposits at the dermal-epidermal junction
C) Infiltrating T cells that express predominantly Th2 cytokines
Langerhan cells = professional antigen presenting cells in the skin
B! Dermatitis herpetiformis - Celiac disease
Eosinophilic esophagitis is considered a mixed IgE and non-IgE disease. Dupilumab, only one of two FDA-approved therapies for this disease, works by:
A) Attaching directly to the IL-5Ra receptor on eosinophils
B) Binding free circulating IgE
C) Selectively binding IL-13 to prevent it from attaching to both its receptor subunits (IL-13Ra and IL-13Rb)
D) Binding to the alpha subunit of the IL-4 receptor (IL-4Ra) to block IL-4 and IL-13
D!
A = benralizumab, Fasenra
C = tralokinumab, Adbry
B = omalizumab, Xolair
Which of these allergens are members of the PR Proteins Group 10 (PR10) - aka which are Birch Bet v 1 homologs? Hint: There is more than one correct answer...
Mal d 1
Cor a 1
Hev b 8
Ara h 5
PR10 Bet v 1 homologs: Mal d 1 (apple) and Cor a 1 (hazelnut). Another example: Ara h 8 (peanut)
vs.
Profilin Bet v 2 homologs: Hev b 8 (latex), Ara h 5 (peanut)
Match the allergen with the food sIgE level (kU/L) where a patient is more than 95% likely to have a clinical allergic reaction if ingested:
Egg White >2yo 14
Wheat 5
Cows Milk >1yo 7
Cows Milk <1yo 26
Peanut 15
Egg white >2yo = 7
Egg white <2yo = 0.35
Cows milk <1yo = 5
Cows milk >1yo = 15
Wheat 26
Peanut 14
You must memorize this table in Middletons!!
Unlike milk and egg allergy, peanut allergy occasionally recurs in children who appear to have outgrown their reactivity. What is the approximate risk of recurrence?
A) 1%
B) 3%
C) 5%
D) 10%
D - 10%
Celiac disease has a strong genetic association with:
A) HLA-DQ2
B) HLA-DR4
C) HLA-B27
D) HLA-B51
A! HLA-DQ2 (a1*0501, b1*0201)
Also DQ8
This exact questions was on my boards. You need to memorize this!
HLA-DR4: RA
HLA-B27: Ankylosing spondylitis
HLA-B51: Behcet disease
The best characterized food-allergic reactions involve which of the following EXCEPT:
A) Binding to high-affinity FceRI receptors on mast cells, basophils
B) Binding to low-affinity FceRII receptors on
C) Smooth muscle relaxation
D) Vasodilation
C - smooth muscles contract, not relax
The following major food allergens is associated with systemic reactions:
Ara h 8
Cor a 1
Bos d 4
Tri a 19
Gal d 3
Ara h 8 - Peanut, pollen-food
Cor a 1 - Hazelnut, pollen-food cross-reactivity with Birch
Bos d 4 - alpha-lactalbumin in cows milk (the important one = Bos d 8 = casein)
Tri a 19 - aka omega-5 gliadin with wheat, associated with systemic reactions with FDEIA
Gal d 3 - aka ovotransferrin, minor egg component, a dumb one (the important ones: ovomucoid = gal d 1, ovalbumin = gal d 2.)
BONUS for 100 POINTS: which of these two, gal d 1 or gal d 2 is more common, and is considered the major egg white allergen?
Respective allergenic proteins in finned fish and shellfish that cause anaphylaxis are:
tropomysin and parvalbumin
OR
parvalbumin and tropomysin
finned fish = parvalbumin
shellfish = tropomysin
BONUS question for 100 points: Tropomysins cross-react with which 2 common environmental allergens?
Which should you outgrow the fastest, milk or egg FA?
A. Cows milk, for sure. 85% by 3 years.
B. Definitely egg. 66% by age 2.
C. Ehh they're both about the same
A!
Cows milk: 50% by 1 year, 70% by 2 years, 85% by 3 years. With a more severe phenotype, 21% remain milk allergic by age 16.
Egg: 66% by age 5! With a more severe phenotype, 32% remain allergic by age 16.
A 4 month old infant is admitted to Children's of Alabama with her second episode of pneumonia with hemorrhagic pulmonary infiltrates. At baseline she is failing to thrive and has an iron deficiency anemia. BAL fluid reveals hemosiderin-laden macrophages and there is a serum eosinophilia.
What other lab value is necessary to confirm her suspected diagnosis?
Precipitating IgG antibodies to cow's milk.
Heiner syndrome = aka pulmonary hemosiderosis = a non-IgE-mediated food reaction to cows milk (has also been described with buckwheat).