Food Allergies and Hypersensitivity Disorders

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Questions and Answers

What is the strongest predictive factor for developing an allergic disorder?

Age at exposure

Environmental exposure

Family history (correct)

Dietary habits

Which type of food reaction is classified as an immediate hypersensitivity reaction?

Caffeine reaction

Eosinophilic esophagitis

Lactose intolerance

Anaphylaxis (correct)

What percentage of children reportedly have a food allergy?

6-8% (correct)

1-2%

10-12%

15-20%

In the context of allergic disorders, what is meant by non-IgE mediated reactions?

Delayed hypersensitivity responses Signup and view all the answers

What symptom is NOT typically associated with anaphylaxis?

Drowsiness Signup and view all the answers

Which investigation can help differentiate between IgE mediated and non-IgE mediated food allergies?

Skin prick test Signup and view all the answers

What is the primary management strategy for food allergies?

Avoidance of triggers Signup and view all the answers

What symptom is a classic sign of food allergy in infants?

Rash or urticaria Signup and view all the answers

Which symptom is least likely to be associated with an IgE mediated food reaction?

Rash Signup and view all the answers

What is the typical time frame for onset of symptoms following exposure to an allergen?

Within 1-2 hours Signup and view all the answers

Which treatment is specifically indicated for managing anaphylaxis?

Epinephrine Signup and view all the answers

What other symptoms might accompany gastrointestinal reactions in IgE mediated food reactions?

Nausea and diarrhea Signup and view all the answers

What is critical for the identification of food allergy triggers in patients?

Patient history Signup and view all the answers

What is the appropriate dose for an epinephrine auto-injector in a child weighing up to 25kg?

0.15mg Signup and view all the answers

Which of the following best describes the occurrence of reactions to food allergens?

Reactions are reproducible with each exposure Signup and view all the answers

Which combination of symptoms is characteristic of an anaphylactic reaction?

Wheezing and fainting Signup and view all the answers

What is the primary characteristic of IgE mediated food reactions?

Symptoms can appear within minutes to 2 hours. Signup and view all the answers

Which symptom is not typically associated with food protein induced proctitis?

Vomiting Signup and view all the answers

In non IgE mediated food allergies, which cellular response is primarily involved?

T cell mediated response Signup and view all the answers

What is a common trigger for food protein induced enterocolitis syndrome?

Cow’s milk protein Signup and view all the answers

Which of the following is true about the symptoms of lactose intolerance?

It involves low levels of lactase in the intestine. Signup and view all the answers

Which food allergens are implicated in causing severe gastrointestinal symptoms within hours?

Cereal grains and dairy Signup and view all the answers

What should be included in the management of IgE mediated food reactions?

Epinephrine auto-injector Signup and view all the answers

What is the typical time frame for symptom onset in non IgE mediated food allergies?

After at least 1 hour Signup and view all the answers

Which of these cases is most likely related to food protein induced enterocolitis syndrome?

An infant with blood-tinged stools from breastmilk Signup and view all the answers

What is a crucial step for a patient diagnosed with oat induced enterocolitis syndrome?

Remove oats from the diet Signup and view all the answers

Study Notes

Allergic Disorders

Twenty percent of the general population experiences an allergic disorder.
Family history is the strongest predictor of allergic disorders.
A family history of allergies in one first-degree relative increases the risk to 30-50%.
A family history of allergies in two first-degree relatives increases the risk to 75%.

Objectives

Identify mechanisms of allergic reactions (immediate and delayed hypersensitivity).
Differentiate between food allergy and food intolerance.
Recognize signs/symptoms and management of anaphylaxis.
Describe the pathophysiology of anaphylaxis.
Identify signs and symptoms of food allergies.
List investigations for IgE-mediated and non-IgE-mediated food allergies.
Discuss the long-term management of food allergies.

Allergic Disorders: Overlap

Atopic Dermatitis
Food Allergy
Asthma
Allergic Rhinitis

Risk Factors

Twenty percent of the general population has an allergic disorder.
Family history is the strongest risk factor for allergies.
Individuals with a first-degree relative with an allergic disorder have 30-50% chance of developing an allergy.
Individuals with two first-degree relatives with an allergic disorder have a 75% chance of developing an allergy.

Case Study #1:

Six-month-old presented to the ER with diffuse urticaria and wheezing.
Vitals were stable.
Consumed cow's milk protein 15 minutes before the onset of symptoms.

Adverse Food Reactions

Reactions can be non-immune mediated, immune mediated, or a mixed reaction.
Non-immune reactions include metabolic (like lactose intolerance) or a pharmacologic or toxic reaction (like caffeine or food poisoning).
Immune reactions are either IgE mediated (immediate hypersensitivity) or non-IgE mediated (delayed hypersensitivity).
Mixed reactions involve both immediate and delayed reactions.

Allergic Reaction Mechanism

Allergen enters the body.
Triggers the production of IgE antibodies.
IgE binds to mast cells or basophils.
Subsequent exposure to the same allergen.
Antigen bridges the gap between two antibody molecules.
Degranulation of the cell and release of histamine and other mediators.
Histamine increases permeability and distension of blood capillaries, causing allergic reaction symptoms.

IgE Mediated Food Reactions

6-8% of children and 3-4% of adults experience food allergies.
Detailed medical history essential.
Details of exposure to food during reaction.
Specific symptoms.
Timing of symptoms.
Reproducibility of reactions.

Top Nine Food Allergens (IgE Mediated)

Soy
Eggs
Peanuts
Fish
Sesame
Shellfish
Tree Nuts
Milk
Wheat

IgE Mediated Food Reactions: Exposure Details

Details of exposure.
Previous exposure to foods?
Route of exposure (ingestion, contact, inhalation).

IgE Mediated Food Reactions: Symptoms: Cutaneous

Cutaneous symptoms are common.
Urticaria (hives) and angioedema (localized swelling) are the most typical.

IgE Mediated Food Reactions: Symptoms: Respiratory

Respiratory symptoms are common.
Rhinorrhea (runny nose), cough, wheeze, shortness of breath.

IgE Mediated Food Reactions: Symptoms: Gastrointestinal

Gastrointestinal symptoms include nausea, abdominal pain, vomiting, and diarrhea.

IgE Mediated Food Reactions: Symptoms: Cardiovascular

Cardiovascular symptoms such as fainting and hypotension can be present.

IgE Mediated Food Reactions: Timing

Reactions typically begin within minutes to two hours of exposure.
Reactions usually resolve within a few hours.

Case Study #1: Continued

Foods suspected: cow's milk protein.
Details of exposure: Cow's milk protein formula.
Specific symptoms: urticaria and wheeze.
Timing of symptoms: 15 minutes after the ingestion of cow's milk protein.
Reproducibility of reaction: Identical reaction with previous exposures to cow's milk protein.
Diagnosis: Anaphylaxis.
Anaphylaxis is a serious life-threatening reaction to an allergen.

Management

Discontinue or remove the allergen.
Intramuscular epinephrine injection.
Intravenous fluids.
Antihistamines help only with hives.
All patients should be discharged with an epinephrine auto-injector.

Epinephrine Auto-Injector

Available auto-injectors include EpiPen®, EpiPen Junior®, Allerject®, and Emerade®.
Dosage depends on patient weight: (0.15mg up to 25kg; 0.3mg patients over 25kg).

Trigger Avoidance

One-third of ER patients have an identifiable trigger.
Common allergens include peanuts, tree nuts, shellfish, fish, milk, eggs, soy, wheat, and others.

Allergy Referral

History is paramount.

Skin Prick Testing

Proteins placed on skin.
Food, aeroallergens, venom, and medications are tested.
Localized hives indicate sensitization to allergen.

Serum Specific IgE

Second antibody with labeling fluorescence.
Identifying allergen specific antibody.

IgE Mediated Food Reactions: Additional Management

Food avoidance.
Epinephrine auto-injector prescription.
Anaphylaxis action plan.
Medical identification device.

Case Study #2

Seven-month-old referred for suspected food allergy.
Foods suspected: oats.
Details of exposure: Ate 3 spoonfuls of oat cereal.
Specific symptoms: profuse vomiting and lethargy.
Timing of symptoms: 3 hours after ingestion.
Reproducibility of reactions: Same reaction with previous oat cereal consumption.
Diagnosis: Oat-induced enterocolitis syndrome.
Treatment: Remove oats from the diet.

Non-IgE Mediated Food Allergy

Immune-mediated reaction involving T-cells.
Gastrointestinal symptoms are typical and may include proctitis (rectal inflammation), and enterocolitis (inflammation in the small and large intestines).

Food Protein Induced Proctitis

Exclusively breastfed infants (2-8 weeks old).
Transfer of food proteins through breastmilk.
Common triggers: Cow's milk protein, egg, soy, corn.
Blood-tinged stools are often present (otherwise healthy).
Skin testing and specific IgE are often not helpful.

Food Protein Induced Enterocolitis Syndrome (FPIES)

Onset symptoms within 1-4 weeks after introducing the food.
Common triggers: Cow's milk protein, soy, grains, rice, meat, poultry, egg, potato, legumes.
Repetitive vomiting (1-3 hours after ingestion).
Skin testing and specific IgE are often not helpful.

Case Study #3

Seventeen-year-old referred for suspected food allergy.
Foods suspected: cow's milk protein foods.
Details of exposure: Symptoms occurred after large amounts of cow's milk protein but the teen tolerated smaller amounts.
Specific symptoms: diarrhea, cramping, and bloating.
Timing of symptoms: 30 minutes after ingestion.
Reproducibility: Same reaction with subsequent yogurt and cheese consumption.
Diagnosis: Possible lactose intolerance or other non-IgE mediated reaction.
Treatment: Determine cause (lactose intolerance) and remove the trigger from diet.

Lactose Intolerance

Non-immune mediated response.
Caused by low levels of lactase, an enzyme in the small intestine.
Signs and symptoms include diarrhea, abdominal pain, bloating.

Case Study #3 (Continued)

Patient diagnosed with lactose intolerance.
Consumes lactose-free products.

Summary of Food Reactions

Food reactions are classified as immune-mediated (IgE or non-IgE) and non-immune mediated.
IgE-mediated (immediate) reactions present rapidly (within minutes) with a variety of symptoms involving skin, respiratory, gastrointestinal, and cardiovascular systems.
Non-IgE (delayed) reactions present later (at least one hour) and typically involve gastrointestinal symptoms.
Anaphylaxis is a life-threatening condition necessitating prompt epinephrine treatment.

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Description

Test your knowledge on food allergies, their classification, and management strategies. This quiz covers everything from allergic reactions to symptom identification and investigative approaches. Discover how well you understand the mechanisms behind food allergies and their impact on health.