Food Allergy and Adverse Reactions to Foods: a Classification System

The Allergy Dude sees so many patients with adverse reactions to foods, he thought it would be a good idea to list his classification of the types of adverse reactions to foods.  I want to give credit to both the Guidelines on the Diagnosis and Management of Food Allergies in the U.S. and World Allergy Organization, whose classification systems the Allergy Dude has modified.  I think for the better (below).  Comments and examples are in parenthesis.

I. Food Allergy

  A. IgE-mediated: urticaria, angioedema, oral allergy syndrome, acute rhinitis, acute asthma, anaphylaxis

  B. Mixed IgE-mediated and non-IgE-mediated: atopic dermatitis, eosinophilic esophagitis, eosinophilic gastroenteritis

  C. non-IgE-mediated: contact dermatitis, protocolitis, food protein-induced enteropathy syndrome, celiac disease, Heiner's syndrome

II. Food Intolerance (not an allergy nor immune mediated)

  A. Food characteristics

    1. Pharmacologic (caffeine, tyramine)

    2. Toxin (bacterial, scromboid fish poisoning)

  B. Host characteristics

    1. Metabolic (lactase or fructase deficiency)

      a. Congenital

      b. Environmental (temporary following GI infection)

    2. Psychological (aversion, panic disorder)

  C. Idiopathic/undefined (sulphites)

  D. Excessive intake (from excess intake: greasy, spicy, hot foods) [D-F = NK modifications]

  E. GI disease (all may affect normal functioning)

  F. GI dysfunction (not outright nor clear cut disease)

    1. Congenital (Irritable bowel syndrome)

    2. Senile (old age)