Is repeat allergy testing advised for oral allergy syndrome patients with reactions to cooked allergenic foods?

Repeat Allergy Testing for Oral Allergy Syndrome with Reactions to Cooked Foods

Repeat allergy testing is strongly recommended for oral allergy syndrome (OAS) patients who experience reactions to cooked forms of allergenic foods, as this indicates potential systemic food allergy rather than typical OAS and requires comprehensive re-evaluation. 1

Understanding OAS vs. Systemic Food Allergy

Oral allergy syndrome (also called pollen-food syndrome) typically causes mild, transient symptoms limited to the oral cavity when consuming raw fruits and vegetables. Key distinctions:

• Typical OAS:

  • Usually involves only mild oral symptoms
  • Allergenic proteins are typically heat-labile (destroyed by cooking)
  • Cooked or processed forms are usually tolerated 1

• Reactions to cooked foods suggest:

  • Presence of heat-stable allergens that aren't fully denatured by cooking
  • Possible true food allergy rather than simple cross-reactivity
  • Higher risk for systemic reactions 1, 2

Indications for Repeat Allergy Testing

Repeat testing is particularly important when:

1. Symptoms have changed or worsened over time 1
2. Reactions occur to cooked/processed forms of trigger foods 1
3. Any systemic symptoms develop beyond the oral cavity 2
4. To identify specific trigger foods for better management 1

Testing Approach for OAS with Reactions to Cooked Foods

The American Academy of Allergy, Asthma, and Immunology recommends a comprehensive approach:

1. Skin prick testing (SPT) to identify sensitization to specific pollens and foods 1
2. Serum-specific IgE testing to measure antibodies to suspected allergens 1
3. Component-resolved diagnostics to identify specific allergenic proteins:
   • PR-10 proteins (Bet v 1 homologs) and profilins: typically cause only OAS
   • Lipid transfer proteins and storage proteins: associated with systemic reactions 3, 4
4. Medically supervised oral food challenges with cooked forms of trigger foods 1

Management Based on Testing Results

The management strategy should be tailored based on testing results:

• If testing confirms only pollen cross-reactivity:

  • Antihistamines before consuming trigger foods
  • Trying cooked or processed forms under medical supervision 1

• If testing reveals true food allergy components:

  • Complete avoidance of the trigger food in all forms
  • Prescription of epinephrine auto-injector
  • Nutritional counseling to prevent deficiencies 1

Cautions and Considerations

• Avoid unnecessary dietary restrictions: Excessive food avoidance can lead to nutritional deficiencies, weight loss, and compromised nutritional status 1

• Risk of severe reactions: Recent studies show that OAS patients can experience systemic and even anaphylactic reactions, particularly with concentrated forms of plant foods (smoothies, juices, supplements) 2

• Supervised reintroduction: For patients with any history of systemic reactions, reintroduction of foods should occur under medical supervision 1

• Consider cofactors: Exercise, alcohol, NSAIDs, and other factors may increase the risk of systemic reactions in OAS patients 2

Repeat allergy testing provides crucial information for risk stratification and appropriate management of OAS patients who react to cooked foods, helping to distinguish between simple OAS and potentially more serious food allergies.