IGHE and ulcer disease: In a sub-group of these patients who had developed hazelnut-specific IgE during anti-ulcer treatment, not only could sensitization towards hazelnut be confirmed by specific IgE antibodies and positive skin prick tests: hazelnut allergy was proved in 3 out of 5 patients with elevated hazelnut-specific IgE titers after the 3 months treatment with gastric acid-suppression medication also by positive provocation tests [93].