Oral allergy syndrome (OAS) from allergen considered to be contained in apple peel

A 22-year-old Japanese man had sometimes developed oral itching and systemic urticaria after eating a whole apple (pulp and peel) since about twelve years of age. This time he presented with oral and perioral itching after eating a whole peach, accompanied with systemic urticaria and dyspnea. We performed a skin prick test to his right volar arm with peel and pulp of apple and peach, respectively. Positive reactions were observed for the peel and pulp of both fruits. In apple, the reaction to the peel was stronger than to the pulp. The specific IgE of apple and peach were positive in class 2, but that of birch was negative. Furthermore, the specific IgE of apple peel was positive, but that of apple pulp was negative. Clinically, he demonstrated no pollinosis. We diagnosed him to have oral allergy syndrome to apple and peach without any related pollinosis. This is the first report of OAS from apple with a stronger allergic reaction to the peel than the pulp in Japan.