Histamine Intolerance Syndrome (HIS): Plethora of Physiological, Pathophysiological and Toxic Mechanisms and their Differentiation

Background: Non-immunological types of foodstuffs intolerance are reported by about 15 - 20% people of the population. The intolerance of histamine and to some extent of other biogenic amines (such as cadaverine, putrescine, tyramine etc.) plays an important role in the differential diagnosis of the foodstuff intolerances and has to be strictly separated from immunologically mediated foodstuffs reactions (foodstuffs allergies, 2 - 5% of the population). Methods: Clinical data from the Erlangen interdisciplinary data register of allergic and chronic inflammatory gastro-intestinal diseases were analysed respecting the existence of a histamine intolerance, then classified and summarised; in addition a selective literature research was undertaken in May 2011. Results: In non-immunological cases of foodstuffs intolerance, the patient's intolerance of histamine plays quite a significant role, clinically it has been exactly proven only in a small subgroup of patients by standardised blinded provocation reactions. The histamine intolerance syndrome (HIS) often presents in a non-specific manner and has to be separated from other pseudo-allergic reactions, idiopathic intolerance reactions, organic differential diagnosis (for example, chronic infections, allergies, mastocytosis etc.) as well as medicamentous adverse effects and psychosomatic reactions. Conclusion: The clinical picture of histamine intolerance should be definitely assured, after the exclusion of other differential diagnosis, by standardised histamine provocation. The avoidance of histamine and biogenic amines, the use of anti-histaminics and the instauration of a proportionate nutrient matter are the most important therapeutic options next to a detailed education of the patient.