Oral allergy syndrome caused by crown daisy and sesame leaf

Oral allergy syndrome (OAS) is a subtype of food allergy composing of itching sense and edema in the oral cavity, lips, throat, pharynx, and larynx following ingestion of some fresh fruits or vegetables. Although the major pathogenic mechanism of OAS is known to be IgE-mediated response, here we experienced a case of OAS due to crown daisy (CD) and sesame leaf (SL) mediated by a non-IgE antibody mediated mechanism. A 33-year-old female visited our clinic to evaluate numbness of the tongue and gingiva after eating fresh CD and SL for 2 years. The patient had suffered from allergic rhinitis and atopic dermatitis for 20 years and took medications intermittently. There had been a history of food allergy to crab and shrimp. The serum total IgE level was elevated (404 kU/mL). The skin prick test showed strong positive reactions to tree and weed pollens, but not to CD and SL extracts. Enzyme-linked immu-nosorbant assay for detecting serum specific IgE to crude extracts of CD and SL showed negative results. The basophil activation test performed with crude extracts of CD or SL showed significant up-regulation of CD63-positive basophils by both CD and SL. In conclusion, we report a case of OAS due to CD and SL, not associated with pollen allergy, which is shown to be mediated by a non-IgE mediated mechanism.