What are the implications of a positive Immunoglobulin E (IgE) test for food allergy in a child?

From the Guidelines

For a child with a positive Immunoglobulin E (IgE) test for food allergy, the primary recommendation is strict avoidance of the triggering food, along with comprehensive counseling and emergency preparedness measures, as outlined in the most recent guidelines 1. The implications of a positive IgE test for food allergy in a child are significant, and management strategies should prioritize strict dietary avoidance of the culprit food allergen, as well as an anaphylaxis management plan that includes ready access to injectable epinephrine 1. Key considerations include:

• Careful reading of food labels to avoid accidental ingestion of the allergenic food
• Informing schools and caregivers about the allergy
• Carrying emergency medication, such as epinephrine auto-injectors, if prescribed by a doctor
• Creating an emergency action plan that details what to do in case of an allergic reaction
• Regular follow-up with an allergist to reassess the allergy status over time, as some children may outgrow certain food allergies 1. It is essential to note that a positive allergy test result in the absence of clinical symptoms is not adequate to make a diagnosis of food allergy, and comprehensive counseling regarding food allergy management is crucial for patients, families, and caregivers 1. Additionally, ongoing nutritional support and education are vital components of food allergy management, particularly for high-risk groups such as adolescents and young adults 1. By prioritizing strict avoidance, emergency preparedness, and comprehensive counseling, healthcare providers can help minimize the risks associated with food allergies and improve the quality of life for affected children.

From the Research

Implications of a Positive Immunoglobulin E (IgE) Test

A positive Immunoglobulin E (IgE) test for food allergy in a child indicates an immunoglobulin E (IgE)-mediated hypersensitive reaction to food, which can cause a range of allergic symptoms, from common urticaria to fatal anaphylaxis 2. The implications of a positive IgE test include:

• The need for a strict elimination diet to avoid accidental reactions due to involuntary intake of the culprit food 2, 3
• The risk of severe allergic reactions, including anaphylaxis, which can be life-threatening 4, 3
• The importance of carrying an emergency kit with adrenaline, an antihistamine, and an injectable rapid onset-of-action corticosteroid for patients with severe allergies 3
• The potential for cross-allergy to other foods or substances, such as pollens or natural rubber latex 3

Diagnosis and Management

The diagnosis of IgE-mediated food allergies is based on a combination of:

• A detailed medical history 2, 3
• In-vivo and in-vitro research of specific IgE 2
• Elimination diet 2
• Double-blind placebo-controlled food challenge 2, 3 The management of IgE-mediated food allergies currently relies on strict allergen avoidance, but emerging therapies such as oral immunotherapy, sublingual immunotherapy, and epicutaneous immunotherapy are being developed and researched 4, 5

Common Food Allergens

The most common food allergens in children include:

• Cow's milk 3, 6
• Egg white and yolk 3, 6
• Peanuts 4, 3, 6
• Tree nuts 4, 3
• Soy 3, 6
• Wheat 3 The prevalence of food allergies has been increasing over the past twenty years, and it represents a major public health problem in industrialized countries 2