How are food sensitivities diagnosed and managed?

Signs and Symptoms of Food Sensitivities: Diagnosis and Management

Food sensitivities are diagnosed through a combination of medical history, elimination diets, and oral food challenges, with management primarily focused on identifying and avoiding trigger foods to prevent adverse reactions.

Understanding Food Sensitivities vs. Food Allergies

Food sensitivities encompass both food allergies (immune-mediated reactions) and food intolerances (non-immune mediated reactions):

• Food Allergy: An adverse health effect arising from a specific immune response that occurs reproducibly upon exposure to a given food 1

  • Requires both allergic sensitization (presence of allergen-specific IgE) AND development of specific symptoms upon exposure
  • Can cause potentially life-threatening reactions (anaphylaxis)

• Food Intolerance: Adverse reactions to foods without immune involvement 1

  • Example: Lactose intolerance due to inability to digest lactose, causing GI symptoms
  • More common than food allergies in adults (10-20% prevalence) 2

Signs and Symptoms

Food Allergy Symptoms

• Skin: Hives, itching, flushing, swelling
• Respiratory: Wheezing, coughing, shortness of breath, throat tightness
• Gastrointestinal: Nausea, vomiting, abdominal pain, diarrhea
• Cardiovascular: Hypotension, dizziness, fainting
• Anaphylaxis: Rapid onset of multiple system involvement that can be life-threatening 1

Food Intolerance Symptoms

• Primarily gastrointestinal: Bloating, gas, abdominal pain, diarrhea
• Typically dose-dependent (small amounts may be tolerated)
• Not life-threatening but can significantly impact quality of life 2

Diagnostic Approach

1. Medical History

• Timing of symptoms in relation to food ingestion
• Consistency of reactions with specific foods
• Quantity of food required to trigger symptoms
• Family history of allergies or intolerances

2. Diagnostic Testing for Food Allergies

• Skin Prick Tests (SPT): Identify sensitization but not necessarily clinical allergy
• Serum-specific IgE tests: Measure food-specific IgE antibodies
• Note: Positive tests indicate sensitization only; clinical correlation is required 1

3. Elimination Diet

• Gold standard approach for both allergies and intolerances 3, 4
• Process:
  1. Remove suspected trigger foods for 2-8 weeks 5
  2. Monitor for symptom improvement
  3. Systematically reintroduce foods one at a time
  4. Document any recurrence of symptoms

4. Oral Food Challenge

• Definitive diagnostic test for food allergies 1, 4
• Must be performed under medical supervision with emergency equipment available
• Protocol:
  1. Start with very small amounts (0.1-1% of normal portion)
  2. Gradually increase dose every 15-30 minutes
  3. Monitor for objective signs of reaction
  4. Continue until reaching normal portion size or reaction occurs 5

Management Approach

For Food Allergies

1. Complete avoidance of confirmed trigger foods 1
2. Emergency preparedness for accidental exposure:
   • Prescription for self-injectable epinephrine for those with history of severe reactions
   • Written emergency action plan
   • Medical identification (e.g., Medic Alert jewelry) 1
3. Education on:
   • Label reading
   • Cross-contamination risks
   • Restaurant dining precautions
   • Cross-reactive foods 1

For Food Intolerances

1. Targeted elimination diet based on identified triggers 2
2. Gradual reintroduction to determine threshold levels (many can tolerate small amounts)
3. Symptomatic treatment for accidental exposure:
   • Antidiarrheal medications for GI symptoms
   • Enzyme supplements (e.g., lactase for lactose intolerance)

Special Considerations

For Schools and Childcare

• Inform school personnel about child's food allergies
• Create allergen-free eating environment
• Ensure written emergency response plan is available
• Arrange for epinephrine access at school 1

For Anaphylaxis Management

• First-line treatment: Intramuscular epinephrine (anterolateral thigh)
  • Adults and children ≥30kg: 0.3-0.5mg
  • Children <30kg: 0.01mg/kg 5
• Position patient supine with legs elevated
• Call emergency services
• Monitor vital signs continuously
• Consider repeat epinephrine every 5-10 minutes if needed 5

Common Pitfalls to Avoid

1. Relying solely on skin or blood tests without clinical correlation
2. Unnecessarily restrictive diets without confirmed diagnosis
3. Delayed epinephrine administration in anaphylaxis
4. Failure to distinguish between food allergy and food intolerance
5. Inadequate follow-up to determine if sensitivities resolve over time

Food sensitivities can significantly impact quality of life, but proper diagnosis and management can help patients minimize symptoms while maintaining adequate nutrition.