#134: Tiny Tissues, Big Troubles: Navigating Allergies in Kids

February 26, 2025 | By Sam Masur

Audio

Summary:

Join us for an insightful conversation with board-certified allergist Dr. Jessica MacDougall (OHSU). In this episode, we dive deep into the world of seasonal, food, and drug allergies. Learn when you can diagnose and treat seasonal allergies, which foods to introduce early, and how to manage the common but confusing amoxicillin rash. Plus, discover key takeaways like why intranasal treatments are the first line for seasonal allergies and why Epinephrine Autoinjector two-packs should always stay together.

Allergy Pearls

1. First line treatment for allergic rhinitis is intranasal steroids and intranasal antihistamines. Oral antihistamines are used as adjunct therapy. 
2. Seasonal allergies don’t typically present before the age of 3 years of age
3. Early introduction of the following can decrease risk of developing food allergies: cows milk, soy, wheat, sesame, egg, fish, shellfish, peanuts, tree nuts
4. Consider a true IgE mediated food allergy in the case of full body hives within 2 hours of new exposure. Localized reactions unlikely represent true allergy
5. Please no serum IgE panels for diagnosing food allergies 
6. Full body rash within hours of the first or second dose of antibiotic likely represents true allergy and the drug should be avoided. A full body rash after many days of exposure likely represents delayed hypersensitivity (Type IV) reaction and the drug may be continued
7. Immunotherapy for environmental allergies are curative. Immunotherapy for food allergies only reduce risk of anaphylaxis in case of accidental exposure
8. Effective and consistent counseling is of the utmost importance in the primary care setting as this is the first line for families

Allergy Notes 

OVERVIEW 

1. Food Allergy (IgE vs non IgE (ex FPIES)
2. Allergic Rhinitis ; seasonal or non seasonal (IgE mediated)
3. Asthma; allergic vs non allergic
4. Eczema (IgE vs non IgE mediated)

ENVIRONMENTAL ALLERGIES (Allergic Rhinitis)

Diagnosis

Clinical Diagnosis
Mild to moderate symptoms often allow for clinical diagnosis without further testing. Not typically seen in children <3 years of age 

Skin Prick Testing
Performed by scratching the skin with various allergens and comparing reactions to controls. For children under 11, testing is usually done on the back to prevent interference. Results are available within 15 minutes.

Serum IgE Testing
Serum IgE testing has similar sensitivity and specificity to skin prick testing. However, it’s only used for environmental allergies, not food allergies. Results take 3-4 days, and false positives are common, especially in children with eczema.

Treatment 

Intranasal Steroids (e.g., Fluticasone, Mometasone)

• Dose: 1 spray per nostril daily.
• Must be used daily for efficacy. It’s considered maintenance therapy with no significant long-term side effects, such as growth suppression or nasal tissue damage.
• Technique tip: Use the right hand for the left nostril and vice versa, aiming away from the septum.

Intranasal Antihistamines (e.g., Azelastine)

• Dose for <12 years: 1 spray per nostril twice daily.
• Dose for >12 years: 2 sprays per nostril twice daily.
• Can be used in combination with intranasal steroids. Considered rescue therapy for acute symptoms.

Oral Antihistamines (e.g., Cetirizine, Loratadine)

• Dose for <2 years: 2.5mg daily.
• Dose for preschool age: 5mg daily.
• Dose for >12 years: 10mg daily.
• Can be increased to twice daily if needed, with a maximum of 20mg/day for young children and 40mg/day for older children.

Antihistamine Eye Drops (e.g., Olopatadine)

• Dose: 1 drop per eye once daily.
• Tip: Store in the fridge for younger kids to reduce the burning sensation.

Mast Cell Stabilizing Eye Drops (e.g., Ketotifen)

• Dose: 2 drops per eye once daily.
• Recommended if antihistamine eye drops alone do not provide sufficient relief.

Sinus Rinse
Use boiled and cooled water or distilled water to avoid infections. May enhance the effectiveness of intranasal treatments. Budesonide saline rinse can be used in older children.

Allergy Shots (Immunotherapy)
Typically considered after age 9. Shots are tailored to the patient’s allergy profile, with the goal of reducing the IgE response to allergens over 3-5 years of treatment. This treatment is often curative.

FOOD ALLERGIES

Early Introduction
Introduce the “Top 9” allergens early in a child’s diet and maintain exposure 1-2 times per week. The allergens include cow’s milk, egg, wheat, soy, peanut, tree nuts, fish, shellfish, and sesame. Gradual introduction is recommended, starting with a pea-sized amount and increasing over 3 days (Leap Study, 2015).

Equal Care

Ensure all families have access to epinephrine auto injectors to reduce emergency department visits. Help qualifying families sign up for WIC or other benefits – allergy food for early exposure as well as allergy free foods once allergy identified can be expensive! 

Cross-Reactivity

• Minimal cross-reactivity exists between shellfish and fish or peanuts and tree nuts.
• However, cashews and pistachios or walnuts and pecans are highly cross-reactive and should both be avoided if an allergy to one is identified.

Diagnosis

Clinical Diagnosis

Clinical diagnosis of IgE mediated food allergy may be made if full body hives present within 2 hours of new food exposure

Skin Testing
Reserved for foods with known reactions due to the high rate of false positives, which could lead to unnecessary dietary eliminations.

Producer Notes: Be sure to counsel patients to discontinue use of oral antihistamines for 3-5 days prior to testing as ongoing use may interrupt testing results.

Serum IgE panels should not be used to diagnose food allergies.

Other “Non IgE Mediated” Reactions

• Rashes appearing 6+ hours after exposure or those limited to the mouth are usually not due to true food allergies.
• Itchy throat from fresh fruits may indicate Oral Allergy Syndrome and does not require food elimination.

Treatment 

Second-Generation Oral Antihistamines
Used for non-anaphylactic food reactions but should be avoided if anaphylaxis is suspected.

Epinephrine Auto-Injectors
Indicated for anaphylaxis, characterized by full-body hives associated with difficulty breathing, or vomiting. Auto-injectors should always be carried in a two-pack in case an additional dose is required.

Oral Immunotherapy (OIT)
Small amounts of the allergenic food are given under supervision and increased to a maintenance dose. The goal is to reduce the risk of anaphylaxis from accidental ingestion, but it is not curative.

Sublingual Immunotherapy (SLIT)
A small drop of allergen is placed under the tongue. This treatment requires a lower dose than OIT and aims to reduce anaphylaxis risk.

Omalizumab
This recently approved treatment option is expensive and time-intensive, limiting its use in practice.

Drug Allergies

IgE-Mediated Drug Allergy
A true IgE-mediated drug allergy presents with full-body hives within hours of the first or second dose. This should be listed as allergies for future avoidance.

Hypersensitivity Reactions

• Type 1: True IgE-mediated reactions; avoid future use.
• Type 2: Cytotoxic-mediated reactions.
• Type 3: Serum sickness-like reactions, treatable with steroids, and the drug may still be used in the future.
• Type 4: Delayed Hypersensitivity. T cell Mediated (e.g., Stevens-Johnson Syndrome or DRESS) 

Cross-Reactivity
In cases of anaphylaxis to amoxicillin, other penicillins and cephalosporins should be avoided. If there is an IgE-mediated reaction without anaphylaxis, 3rd, 4th, and 5th generation cephalosporins may still be safe. May check specific recommendations here: Practical Guidance for the Evaluation and Management of Drug Hypersensitivity: Specific Drugs (aaaai.org)) 

Direct Challenge
In unclear cases, a direct challenge with an allergist may be recommended. Intradermal skin testing is possible but not recommended for cutaneous-only reactions.

Take-Home Points:

• When in doubt – refer to an allergist 
• Consistent and effective counseling is critical in the primary care setting when discussing allergies and severe reactions they may cause
• No food panel testing please 
• Amoxicillin allergies are rare. In most cases it is safe to continue using this drug in the future

Patient Resources:

• FARE Website: foodallergy.org
• FPIES Organization: fpies.org

Goal

Listeners will be able to explain the diagnosis and management of seasonal allergies, food allergies, and drug allergies. They will learn how to counsel patients in the outpatient setting as well as learn what  testing and treatment options may be offered by an allergy & immunology specialist.

Learning Objectives

After listening to this episode listeners will…  

1. Be able to identify IgE vs non IgE mediated reactions to food and medications
2. Be familiar with first line treatments and advanced treatment options (OIT, SLIT)for seasonal and food allergies
3. Feel comfortable counseling patients about early introduction of “allergens”
4. Be able to identify the appropriate use of skin prick testing vs serum testing for allergies

Disclosures

Dr. MacDougall reports no relevant financial disclosures. The Cribsiders report no relevant financial disclosures. 

Citation

Bagot O, MacDougall J, Berk J, Chiu C, Masur S.. “#134: Tiny Tissues, Big Troubles: Navigating Allergies in Kids”. The Cribsiders Pediatric Podcast. https:/www.thecribsiders.com/ February 26, 2025.