Craig Friesen: Understanding Food Allergies and Food Intolerance in DGBIs

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Dr. Craig Friesen gave our group an excellent update on food allergy and disorders of brain-gut interaction (DGBIs).  His main disclosure was that he is not an allergist. My notes below may contain errors in transcription and in omission. Along with my notes, I have included many of his slides.

Key points:

  • Food allergies are common affecting 6-10% of the population. In infants, milk and egg are common allergens. Nut allergies are more frequently seen in children
  • There are likely hundreds of genes that can predispose towards allergies
  • Food exposures, especially in the 4-6 month range, have been associated with a lower risk of food allergies
  • Food trigger symptoms are present in most patients with DGBIs; however, the lines between immune mechanisms and non-immune mechanisms are often blurry
  • Food allergy testing (skin prick testing, IgE-based blood tests) is not recommended in the absence of systemic symptoms due to poor specificity (perhaps ~10%). Obtaining a careful history is a very important part of determining allergies. Double-blind challenges, which are rarely done, are still considered “gold standard” for diagnosis
  • Mucosal endoscopic provocation (research tool) often discloses localized immune reaction; it does not correlate with skin prick testing or IgE-based blood tests
  • After prior sensitization/food allergies, stressful conditions may create similar symptoms as allergic exposures. This can be mediated by histamine and tryptase/mast cells
  • It is rare for food allergen restriction to “fix” a DGBI. Occasionally, food allergies may be part of the problem. Dietary restrictions may lead to weight loss and contribute to ARFID
  • IgG-based allergy testing (widely available) is not recommended; IgG antibodies are usually indicative of tolerance
  • Environmental pollen counts are associated with increased DGBI symptoms, increased mucosal eosinophils, and less sleep
  • Environmental allergen testing can sometimes be helpful in identifying cross-reacting foods
  • Alpha-gal syndrome. Consider testing in those with symptoms triggered by meat ingestion, and those with refractory symptoms. In pediatric patients, often no rash is identified and many will ‘outgrow’ allergy
  • Oral immunotherapy can be effective in improving tolerance for allergic foods; however, up to 70% will redevelop intolerance
  • When mucosal eosinophilia is identified, there are a number of potential treatments including dietary restrictions, mast cell stabilizers, antihistamines, and steroids

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