Histamine plasma levels and elimination diet in chronic idiopathic urticaria.

Department of Immunology, University ‘Federico II’, Naples, ItalyObjective: The aim of this study was to evaluate the effects of an oligoantigenic and histamine-free diet onpatients affected with chronic idiopathic urticaria (CIU).Design: Ten patients with chronic idiopathic urticaria were prescribed an oligoantigenic and histamine-free dietfor 21 days, followed by serial and controlled reintroduction of foods during a further 70 days. Modification inclinical illness as well as histamine plasma levels, post-heparin plasma diamine oxidase (DAO) and intestinalpermeability were evaluated.Results: The oligoantigenic and histamine-free diet induced a significant improvement of symptoms (P<0.05).Moreover, CIU patients on free diet showed higher histamine plasma levels (P<0.05 vs post-diet and vscontrols) that fell to control levels during the oligoantigenic and histamine-free diet. Post-heparin plasmadiamine oxidase values were slightly reduced and were unchanged during the diet as well as intestinalpermeability, which was always normal in all patients.Conclusions: These data suggest that histamine plays a major role in chronic idiopathic urticaria. The finding ofnormal intestinal permeability suggests that a morphological damage of intestinal mucosa should be excluded inthese patients. However, the presence of low levels of post-heparin plasma diamine oxidase may indicate asubclinical impairment of small bowel enterocyte function that could induce a higher sensitivity to histamine-rich or histamine-producing food.Descriptors: chronic idiopathic urticaria; diet; histamine; diamine oxidase; intestinal permeabilityEuropean Journal of Clinical Nutrition (2000) 54, 155–158