Pediatric Food Allergies Flashcards by michelle granstrom

Q

What is the difference b/w a food allergy & a food intolerance?

A

Food Allergy–>immunologically mediated

Food Intolerance–>non-immunologically mediated

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Q

T/F People often get the hives for no reason at all.

A

True. Then they associate whatever they were eating with their reaction.

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Q

What are the subcategories of food allergies?

A

All immunologically mediated

*some disorders mediated by IgE (this is the immunoglobulin that creates hay fever)
*some disorders mediated by IgG, sensitized lymphocytes, or other mechanisms.

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Q

What category of adverse food rxns does lactose intolerance fall into?

A

Food intolerance b/c non-immunologically mediated.
Lack of lactase enzyme.
Won’t die from drinking milk–>but very unpleasant.

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Q

What is a food that you can get hives from–>that you aren’t necessarily allergic to?

A

Strawberries! there are bunches of histamine in this…can get hives if you have a ton.

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Q

What are the 4 main categories of non-immune adverse food reactions?

A

Food Intolerance: 
Metabolic
Pharmacologic
Toxic
Other

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Q

What are 5 examples of metabolic food intolerance?

A

Lactase Deficiency
Fructose Intolerance
Galactosemia
Pancreatic Insufficiency
Gallbladder/liver disease

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Q

What are 4 examples of pharmacologic food intolerance?

A

histamine
tyramine
caffeine
theobromine

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Q

What are 3 examples of toxic food intolerance?

A

food poisoning
scombroid fish poisoning
ciguaterra fish poisoning

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Q

What are other things that fall into the category of food intolerance?

A

panic, anxiety
hiatal hernia
reflux

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Q

What basic type of food are people usu allergic to?

A

a specific protein in a food, usu not lipids

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Q

What is the usu profile of a food allergen?

A

water-soluble glycoprotein
heat & proteolysis resistant
molecular weight: 10-70kd

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Q

What are the most common food allergens?

A

peanut: Ara h1, Ara h2, Ara h3
chicken egg white: Gal d1, Gal d2, Gal d3
soybean: gly m-1
fish: gad c1
shrimp: pen a1

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Q

What percentage of households report that at least one member of their family has a food allergy? What percentage of infants have a food allergy? What percentage of adults have a food allergy?

A

25-30% of households
6% of infants
3.7% of adults

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Q

What is the prevalence of this allergy in children?

cow milk

A

2.5%

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Q

What is the prevalence of this allergy in children?

eggs

A

1.3%

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Q

What is the prevalence of this allergy in children?

peanuts

A

0.8%

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Q

What is the prevalence of this allergy in children?

wheat

A

0.4%

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Q

What is the prevalence of this allergy in children?

soy

A

0.4%

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Q

What are some common allergic diseases of children?

A

eczema
food allergy
asthma
rhinitis

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Q

Which age population usu has allergies?

A

Children! A disease of children. Usu don’t develop allergies when you are an adult. A lot of food allergies decrease as you age.

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Q

We are talking about adverse reactions to food.

What is an IgE mediated mechanism that is systemic?

A

anaphylaxis

food-associated exercise-induced anaphylaxis

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Q

We are talking about adverse reactions to food.

What is an IgE mediated mechanism that is related to the skin?

A

urticaria

angioedema

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Q

We are talking about adverse reactions to food.

What is an IgE mediated mechanism that is related to GI?

A

immediate GI symptoms

Pollen food allergy syndrome

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We are talking about adverse reactions to food. | What is an IgE mediated mechanism that is related to the respiratory system?

bronchospasms

What is urticaria?

hives

What is angioedema?

swelling

What is atopic dermatitis?

eczema

If you have eczema, does that mean that you have a food allergy?

50% of the time--yes! | 50% of the time--no!

What type of food allergy is gluten in Celiac patients?

Food allergy | non-IgE mediated mechanism

We are talking about adverse reactions to food. | What is a non-IgE mediated mechanism that relates to the skin?

dermatitis herpetiformis

We are talking about adverse reactions to food. | What is a non-IgE mediated mechanism that relates to the GI system?

Celiac disease enteropathy Food-induced enterocolitis syndrome allergic proctocolitis

We are talking about adverse reactions to food. | What is a non-IgE mediated mechanism that relates to the respiratory system?

Heiner's syndrome

We are talking about adverse reactions to food. Mixed b/w IgE & non-IgE mechanisms What is something that relates to the skin?

atopic dermatitis

We are talking about adverse reactions to food. Mixed b/w IgE & non-IgE mechanisms What is something that relates to the GI system?

eosinophilic esophagitis | gastroenteritis

We are talking about adverse reactions to food. Mixed b/w IgE & non-IgE mechanisms What is something that relates to the respiratory system?

asthma

What is the most common mechanism of food hypersensitivity?

IgE mediated

How does an IgE mediated allergic reaction work?

IgE antibodies produced for a specific epitope of the food allergen these IgE antibodies bind to high affinity IgE receptors on basophils & mast cells when exposed to the allergen a second time, 2 adjacent IgE antibodies bind together receptor cross-linking occurs a bunch of factors are released body reacts

Where are the high affinity IgE receptors found that are a part of the IgE-mediated mechanism?

on basophils & mast cells | in skin, GI tract, & resp tract

What substances are released after receptor cross linking of 2 IgE antibodies?

``` histamine prostaglandins leukotrienes chemotactic factors cytokines ```

What are the end reactions that the body experiences w/ an IgE mediated allergic rxn?

vasodilation smooth muscle contraction mucus secretion

Which cell is in charge of making IgE? Which specific cell is recruited to make it?

Th2 cells are responsible for making it. | B lymphocytes in particular make it.

Of the patients who come to the emergency room with anaphylaxis...what percentage of them had a food allergy?

1/3

How fast does an IgE mechanism work?

usually within an hour of ingestion

What symptoms are caused w/ an IgE reaction?

``` urticaria angioedema dyspnea wheezing hypotension oropharyngeal pruritis stridor dysphoma cough nausea vomiting diarrhea flushing "sense of impending doom" ```

What about an IgE reaction can result in fatalities?

severe laryngeal edema irreversible bronchospasm refractory hypotension

What are the most common causes of anaphylactic reactions?

peanuts, tree nuts, shellfish

What are risk factors for an anaphylactic reaction becoming fatal?

not recognizing that it is beginning not getting immediate care previous episodes of anaphylaxis poorly controlled asthma

Can diphenydramine or Benadryl save someone from anaphylaxis?

NO. | Only epinephrine shots.

What is another name for the pollen food allergy syndrome?

oral allergy syndrome

What are the symptoms of the pollen food allergy syndrome?

itching/tingling lips, tongue, palate, or throat edema of the lips, tongue, uvula tightness in the throat

If you have a severe rxn w/ pollen food allergy syndrome-->what happens?

systemic reaction-->laryngeal edema, hypotension

What is the basic explanation for pollen food allergy syndrome?

cross-reactivity b/w certain pollens & food allergens

Most adults who claim to have food allergies have what?

pollen food allergy syndrome

Which foods are cross-reactive for people who are sensitive to ragweed pollen?

bananas pumpkins melons

Which foods are cross-reactive for people who are sensitive to birch pollen?

``` raw carrots celery potato apple hazelnut peach kiwi ```

Which foods are cross-reactive for people who are sensitive to alder pollen?

almonds apples strawberries

Which foods are cross-reactive for people who are sensitive to grass pollen?

figs melons tomatoes oranges

What are the main ways to test for food allergies? Which one is the gold standard?

Skin tests RAST tests Patch tests Food Challenges: gold standard, double blinded

Describe allergy prick testing.

this tests immediate hypersensitivity to IgE mediated things, like fresh fruits & vegetables allergies you read the test 20 minutes after you prick the skin.

What are the advantages to allergy prick testing? What are the disadvantages?

Advantages: cheap, convenient, inexpensive Disadvantages: limited to IgE mediated hypersensitivity & has a false positive rate > 50% **why it is important to not use to test 100 different things **if you have taken any antihistamines-->the test is worthless

Would an allergy prick test work to test someone for Celiac disease?

No. it is NOT IgE-mediated

Describe RAST testing.

This is also used for IgE-mediated allergies. It is a blood test that checks for serum levels of IgE against certain foods.

What are the advantages & disadvantages of RAST testing?

Advantages: histamines don't compromise the result Disadvantages: false positive rate even higher! 70%

Would it work to test for an IgG mediated mechanism with a RAST test?

NO!

Can food allergies cause behavioral problems?

NO

Describe allergy patch testing.

* patches are put on the skin w/ nickel or some food particles * no bathing allowed * it can be read at 48-72 hours * tests delayed hypersensitivity sometimes via sensitized lymphocytes * *can sometimes be used for non-IgE mediated food allergies

What are some conditions that allergy patch testing can help identify?

food protein induced enterocolitis syndrome | eosinophilic esophagitis

What are some of the weaknesses of allergy patch testing?

false positive rates & false negative rates | messy preparation

What are food challenges?

double-blinded placebo-controlled used when diagnosis must be confirmed observed incremental changes in the amount of the food in question. epinephrine w/ crash cart must be available.

What is FPIES?

food protein induced enterocolitis syndrome | severe, cell-mediated GI food hypersensitivity

What are the symptoms of FPIES? What usu provokes this condition?

usu provoked by cow's milk or soy | delayed onset of vomiting, diarrhea, & lethargy/dehydration

Do the symptoms of the severe condition of FPIES include rash, wheezing, & swelling?

NO.

Aside from cow's milk & soy, what other foods can prompt the symptoms of FPIES?

grains (rice, oats, barley) vegetables (sweet potato, squash, string beans, peas) poultry (chicken, turkey)

Describe the usual level of severity of FPIES.

79% severe 57% sepsis resulted 64% hospitalized for dehydration or shock

What is eosinophilic esophagitis?

an issue where you can easily get strictures in your esophagus, have trouble eating/swallowing similar to asthma eosinophilic responds to steroids chronic condition strongly associated w/ allergies (food, pollens)

T/F Asthma is an eosinophilic disease.

True.

Why is eosinophilic esophagitis called by this name?

b/c if you take a biopsy of the strictured esophagus-->you will find a bunch of eosinophils.

A lot of people with eosinophilic esophagitis also have some other conditions. Which conditions?

asthma pollen allergy hay fever eczema

Younger patients w/ eosinophilic esophagitis show more sensitization w/ what? Older adults-->show more sensitization w/ what?

Younger: IgE & patch sensitization Adults: inhalant allergens

What is the appropriate treatment for food allergies?

complete avoidance of the food | keep an epinephrine injector with them

What is the treatment for eosinophilic esophagitis?

practice an elemental diet systemic corticosteroids (like prednisone) topical corticosteroids allergy shots

What are 2 kinds of topical corticosteroids?

swallowed MDI fluticasone | budesonide slurry

If FPIES IgE-mediated?

No.

Do epinephrine injections require training?

Yes.