In two patients with leukocytoclastic vasculitis allergic reactions to foods were shown to be of clinical relevance. Intracutaneous tests with food allergens produced not only immediate wheal and flare reactions but also distinct inflammatory reactions after 8-24 h, which showed the histological and immunopathological characteristics of leukocytoclastic vasculitis. After controlled oral provocation with specific foods exacerbation of petechial lesions was observed. A striking improvement in the patients' condition was achieved by avoidance of the relevant foods and oral administration of cromoglycate.