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.