The differential diagnosis of food intolerance

Abstract

Introduction: More than 20% of the population in industrialized countries suffer from food intolerance or food allergy.

Methods: Selective literature search for relevant publications in PubMed and the Cochrane Library combined with further data from the interdisciplinary database on chronic inflammatory and allergic diseases of the Erlangen University Hospital.

Results: The majority of cases of food intolerance (15% to 20%) are due to non-immunological causes. These causes range from pseudoallergic reactions to enzymopathies, chronic infections, and psychosomatic reactions that are associated with food intolerance. The prevalence of true food allergy, i.e., immunologically mediated intolerance reactions, is only 2% to 5%.

Conclusions: The differential diagnosis of food intolerance is broad. Therefore, a structured diagnostic algorithm with input from multiple clinical disciplines should be applied. The treatment consists of eliminating the offending substance from the diet as well as medications and psychosomatic support, when indicated.

Keywords: Food intolerance; critical appraisal; decision making; diagnosis; food allergy; histamine intolerance; provocative testing; quality assurance; study.

Figures

Figure 1

Overview of range of food intolerance reactions

Figure 2

Examples of important functional and structural causes of food intolerances; anti-tTG antibodies, antibodies to tissue transglutaminase; EHEC, entero-toxic Escherichia coli; ETEC, entero-hemorrhagic Escherichia coli; CIBD, chronic inflammatory bowel disease

Figure 3

Overview of diagnostic approaches to the differential diagnostic spectrum of food intolerances and allergies; *1 both clinical pictures can also coexist; ESR, erythrocyte sedimentation rate; GPT, glutamate pyruvate transaminase; NSE neuron specific enolase; ERCP, endoscopic retrograde cholangio-pancreaticography

Figure 4

Immunological mechanisms in food allergies (gastrointestinally mediated Grade I-IV allergies) according to Coombs and Gell