Peach-Induced Contact Urticaria Is Associated with Lipid Transfer Protein Sensitization

BACKGROUND: Peach-induced contact urticaria is frequent in peach-allergic subjects. OBJECTIVE: It was the aim of this study to detect whether contact urticaria is associated with a specific peach allergen. METHODS: Ninety-two peach-allergic subjects were studied. Patients were diagnosed as being sensitized to lipid transfer protein (LTP; Pru p 3) or as having a pollen-food allergy syndrome induced by Pru p 1 and/or profilin, Pru p 4, on the basis of the results of a skin prick test containing these allergenic proteins in an isolated form. Specific IgE to peach extract was measured as well. Contact urticaria was confirmed by a contact test with intact, untreated peach. A contact test with nectarine was carried out as control. RESULTS: Overall, contact urticaria was present in 21% of patients; the peach contact test scored positive in all cases. Contact urticaria was significantly more frequent in patients hypersensitive to LTP (63%) than in subjects with pollen-food allergy syndrome (6%; p < 0.001) and was not associated with a higher level of peach-specific IgE. In several cases, contact urticaria preceded the onset of food allergy by years. The contact test with nectarine scored negative in 5/5 cases. CONCLUSIONS: Although the peach contact test was not performed in all subjects, and peach allergy was not confirmed by oral challenges, this study shows that peach-induced contact urticaria is associated with sensitization to peach LTP. The negative clinical history and contact test with nectarine along with the well-known high concentration of LTP in peach fuzz suggest that peach fuzz plays a role in the pathogenesis of contact urticaria.