How are food sensitivities tested for in patients with suspected eosinophilic gastroenteritis?

Testing for Food Sensitivities in Eosinophilic Gastroenteritis

The gold standard for identifying food triggers in eosinophilic gastroenteritis is dietary elimination followed by systematic food reintroduction with endoscopic biopsy confirmation—not allergy testing alone. 1, 2

Definitive Diagnostic Approach

Food triggers can only be definitively identified by documenting disease remission (histologic resolution) after specific food elimination, followed by recurrence of eosinophilia upon food reintroduction. 1, 2 This requires:

• Elimination phase: Remove suspected foods for 6-8 weeks 2
• Endoscopic confirmation: Perform endoscopy with biopsies to document histologic response (goal: <15 eosinophils per high-power field for esophageal involvement, >20 eosinophils per high-power field for gastric/duodenal involvement) 2, 3
• Systematic reintroduction: Reintroduce foods one at a time with repeat endoscopy to identify specific triggers 1, 2

Empiric Elimination Diet Strategy

The most practical approach is the empiric 6-food elimination diet (dairy, eggs, wheat, soy, peanuts/tree nuts, fish/seafood) without prior allergy testing, which achieves efficacy in 73-74% of patients. 2, 4 This approach:

• Does not require allergy testing beforehand 2, 4
• Is more practical than elemental (amino acid-based) formulas, which have 92-98% efficacy but poor adherence 2
• Requires supervision by an experienced dietitian to ensure adequate nutrition 2

Limited Role of Allergy Testing

Allergy tests (skin prick tests, serum-specific IgE, atopic patch tests) may help identify candidate foods for elimination but are NOT sufficient alone to diagnose food-triggered eosinophilic gastroenteritis. 1, 2, 4

Why Allergy Tests Have Limited Utility:

• Poor predictive accuracy: Only 13% concordance between allergy test results and actual food triggers identified through reintroduction 2
• Low positive predictive value: IgE-based tests (skin prick, serum IgE) and RAST have poor correlation with tissue inflammation and symptom improvement 2, 4
• Non-IgE mechanism: Eosinophilic gastroenteritis primarily involves a delayed, cell-mediated (Th2) hypersensitivity response rather than immediate IgE-mediated reactions 4, 5

When Allergy Testing May Be Considered:

• As a complementary tool only: Tests can help generate a list of foods to investigate further through elimination and reintroduction 1
• Safety screening: Patients with positive IgE tests should be evaluated for risk of immediate hypersensitivity reactions during reintroduction and prescribed epinephrine if indicated 1
• Combined testing: The combination of skin prick tests and atopic patch tests may increase identification of potential allergens, though this remains unvalidated 2

Critical Implementation Points

Endoscopic Requirements:

• Multiple biopsies essential: Obtain 5-6 random biopsies from stomach and duodenum to increase diagnostic yield 6
• Repeated procedures necessary: Symptoms do not correlate with histologic activity, requiring repeat endoscopy after elimination and with each reintroduction 2
• Exclude other causes: Rule out parasitic infections, medications, autoimmune diseases, and hypereosinophilic syndrome before attributing eosinophilia to food 4, 3

Important Caveats:

• Risk of de novo IgE-mediated allergy: Food reintroduction after prolonged elimination may trigger immediate allergic reactions; medical supervision is mandatory 1, 2
• High resource utilization: Patients average 5 endoscopic procedures per year during diagnosis and management 7
• Long-term adherence challenges: Maintaining dietary restrictions after identifying triggers is difficult 1, 2
• Spontaneous remission possible: 30-40% of patients may achieve spontaneous remission without treatment 3, 6

Practical Algorithm

1. Start empiric 6-food elimination diet without allergy testing 2, 4
2. Endoscopy with biopsies at 6-8 weeks to document histologic response 2
3. If remission achieved: Systematically reintroduce foods one at a time with repeat endoscopy 2
4. If no response: Consider elemental (amino acid) formula or corticosteroids 2, 4
5. Optional: Use allergy testing to prioritize which foods to reintroduce first, but never rely on testing alone 1, 2