How to interpret an IgE (Immunoglobulin E) profile report in a child with elevated IgE levels but no definite intolerance to any particular food or allergen?

Interpreting IgE Profile Reports in Children with High IgE Levels but No Definite Food Intolerance

Elevated IgE levels alone are not sufficient to diagnose food allergy, as the presence of allergen-specific IgE does not necessarily indicate clinical disease. 1

Understanding IgE Testing in Children

• IgE testing has poor positive predictive value - tests are sensitive and generally detect allergen-specific IgE that is present, but simply having allergen-specific IgE is not indicative of having a true allergy 1
• Allergy testing cannot predict future risk and should only be used to evaluate suspected allergic reactions that have already occurred 1
• A positive allergy test result in the absence of clinical symptoms is not adequate to make a diagnosis of food allergy 1

Clinical Approach to Interpreting Results

When High IgE Levels Are Found:

• Consider that elevated IgE levels may indicate:

  • Atopic conditions (eczema, asthma) 2
  • Possible inborn errors of immunity (in cases of extremely elevated IgE) 2
  • Sensitization without clinical allergy 3

• For inhalant allergens, specificity and sensitivity of IgE testing are within 85-95% range, but these values decrease for food allergens 3

Recommended Algorithm for Interpretation:

1. Correlate with clinical history:

   • Has the child experienced any symptoms after food ingestion? 1
   • Document timing of symptoms in relation to food exposure 1

2. Consider the specific IgE levels:

   • A cutoff level of 2 kUA/L for milk, egg, and peanut corresponds to approximately 50% likelihood of clinical reactivity 4
   • Class 2 or greater is generally interpreted as clinically significant 3
   • Class 1 is considered dubious or negative depending on the allergen 3
   • Class 0 is negative 3

3. Evaluate for clinical reactivity:

   • Oral food challenges remain the gold standard for diagnosis of food allergy 4
   • Consider challenges for foods with positive IgE but no clear history of reaction 4

Common Pitfalls to Avoid

• Overreliance on testing: Do not interpret results too literally, especially in children with atopic dermatitis where the relationship between food-specific IgE and food allergy is often overspecified 1

• Unnecessary dietary restrictions: For children without documented food allergy, avoiding potentially allergenic foods is not recommended as a management strategy for atopic dermatitis, asthma, or eosinophilic esophagitis 1

• Premature diagnosis: Food allergy diagnosis requires documentation of a clinical history of a food allergic reaction, not just positive test results 1

• Missing non-IgE mediated reactions: Some food allergies present with delayed symptoms and may not correlate with IgE testing 5

When to Refer to an Allergist

• Children with moderate-to-severe atopic dermatitis despite optimized management 1
• Children with reliable history of immediate reaction after ingestion of a specific food 1
• When IgE results are difficult to interpret in the clinical context 1

Follow-up Recommendations

• Regular follow-up is recommended for retesting, especially for common childhood food allergies like milk and egg, which are often outgrown 1
• Nutritional counseling and regular growth monitoring are recommended for all children with food allergy 1

Remember that the diagnosis of food allergy is based on the combination of clinical history, physical examination, and supportive laboratory findings, not on IgE levels alone 1.