What is the appropriate workup and management for a suspected wheat (gluten) allergy?

Workup and Management of Suspected Wheat (Gluten) Allergy

For suspected wheat allergy, begin with skin prick testing or serum-specific IgE testing to wheat proteins, but confirm the diagnosis with an oral food challenge under medical supervision, as positive tests alone do not establish clinical allergy. 1

Initial Diagnostic Approach

Clinical History Assessment

• Document the timing of symptoms relative to wheat ingestion—IgE-mediated reactions typically occur within minutes to hours after exposure 1, 2
• Identify specific symptom patterns: cutaneous (urticaria, angioedema), respiratory (wheezing, throat tightness), gastrointestinal (nausea, vomiting, diarrhea), or cardiovascular (hypotension, syncope) manifestations 3, 2
• Assess for exercise-induced anaphylaxis triggered by wheat, which occurs when wheat ingestion is followed by physical activity within 4-6 hours 1
• Evaluate for occupational exposure to wheat flour (baker's asthma) if respiratory symptoms predominate 2
• Screen for coexisting asthma, which increases the risk of severe reactions 4-fold and represents a critical risk factor for fatal anaphylaxis 4, 1

Diagnostic Testing Algorithm

Step 1: Initial Testing

• Perform skin prick testing as the test of choice using fresh wheat flour extracts (standardized extracts are not available) 1
• Alternatively, measure serum-specific IgE to wheat proteins, including omega-5 gliadin, which is particularly relevant for wheat-dependent exercise-induced anaphylaxis 1
• Testing should identify IgE antibodies to albumin, globulin, gliadin, and glutenin fractions 2, 5

Critical Pitfall: Positive skin tests or elevated specific IgE levels indicate sensitization only, not clinical allergy—50-90% of presumed food allergies based on testing alone are not true allergies 1, 4

Step 2: Confirmatory Testing

• Conduct an oral food challenge when history and testing results are discordant or when definitive diagnosis is needed 1
• Use a graded challenge protocol starting with 0.01g wheat flour (0.1% of total dose), escalating every 15 minutes to a total of 10g wheat flour over 90 minutes 1
• Perform challenges only in a medical facility with personnel trained to treat anaphylaxis and with epinephrine immediately available 1
• For suspected wheat-dependent exercise-induced anaphylaxis, consider oral challenge with wheat followed by exercise, or wheat plus aspirin and alcohol 1

Step 3: Specialized Testing (When Indicated)

• Measure serum tryptase during acute reactions to confirm anaphylaxis 1, 3
• Consider testing for recombinant omega-5 gliadin (Tri a 19) for suspected exercise-induced anaphylaxis 1
• Perform esophagogastroduodenoscopy with biopsy if non-IgE-mediated eosinophilic esophagitis or gastritis is suspected (chronic symptoms, no immediate reactions) 2

Management Strategy

Immediate Management of Acute Reactions

Epinephrine is the first-line treatment for anaphylaxis—all other medications have delayed onset and are adjunctive only. 1, 3

• Administer intramuscular epinephrine immediately when anaphylaxis is suspected (do not delay for antihistamines) 1, 3
• Place patient supine with legs elevated (if tolerated) 1
• Provide supplemental oxygen and IV fluid resuscitation 1
• Repeat epinephrine every 5-15 minutes if symptoms persist or progress 1
• Use antihistamines and corticosteroids only as adjunctive therapy, not as substitutes for epinephrine 1, 3

Common Pitfall: Antihistamine use is the most common reason for failure to administer epinephrine, significantly increasing risk of progression to life-threatening reactions 1

Long-Term Management

All patients with confirmed wheat allergy require four mandatory interventions: 4

1. Strict Dietary Avoidance

   • Eliminate all wheat-containing foods and products 4, 2
   • Provide comprehensive education on label reading to identify wheat proteins (albumin, globulin, gliadin, glutenin) 4
   • Avoid products with precautionary allergen labeling due to contamination risk 4
   • For wheat-dependent exercise-induced anaphylaxis specifically, avoid exercise for 4-6 hours after wheat ingestion 1

2. Emergency Medication Prescription

   • Prescribe two epinephrine autoinjectors (patient should carry both at all times) 4, 1
   • Prescribe antihistamines for mild, non-systemic reactions 4, 3

3. Nutritional Counseling

   • Arrange consultation with dietitian for regular growth monitoring and nutritional adequacy assessment 4
   • This is particularly critical in children with multiple food allergies (30.4% of food-allergic children have multiple allergens) 4

4. Comprehensive Patient Education

   • Train on recognition of anaphylaxis symptoms 4
   • Demonstrate proper epinephrine autoinjector technique 4
   • Develop written emergency action plan 4
   • Address quality of life concerns and anxiety management 4

Special Considerations

For Children:

• Wheat allergy is more common in children and may be outgrown during adolescence 2, 6
• Consider periodic retesting (skin tests or specific IgE) to assess for tolerance development 4
• Children with severe eczema in first 6 months have increased risk of wheat allergy 4

What NOT to Do:

• Do not use intradermal testing (higher risk, no diagnostic advantage) 1
• Do not implement wheat avoidance based solely on positive tests without clinical correlation 1, 4
• Do not recommend oral or sublingual immunotherapy outside research settings (carries risk of severe reactions) 4
• Do not use total serum IgE or atopy patch testing for routine wheat allergy diagnosis 1

Follow-Up Protocol

• Schedule regular follow-up with allergist for reassessment 4
• Monitor for development of other atopic conditions 4
• Reassess need for continued avoidance, particularly in children showing declining specific IgE levels 4