We report two cases of anaphylaxis due to ingestion of mite-contaminated Okonomi-yaki (Japanese pancake) mix. Case 1: A 50-year-old female developed anaphylaxis after eating Okonomi-yaki prepared from Okonomi-yaki mix that had been stored at room temperature after opening. She demonstrated serum specific IgE against
Dermatophagoides farinae (
Der. f.), but did not demonstrate any wheat- or gluten-specific IgE antibodies. Prick tests showed positive reactions to
Der. f. antigen (Torii) but not to previously unopened Okonomi-yaki mix or wheat flour that had been stored in a freezer. Case 2: A 28-year-old female developed anaphylaxis after eating Monja-yaki prepared from Okonomi-yaki mix that had been stored at room temperature after opening. She demonstrated serum specific IgE antibodies against
Der. f. but no wheat- or gluten-specific IgE antibodies. Prick tests showed positive reactions to the responsible Okonomi-yaki mix and
Der. f. antigen (Torii), but not to wheat flour that had been stored in a freezer. The responsible Okonomi-yaki mix contained 50 heads/g of
Der. f., and a high level (64.1 μg/g) of
Der f1 antigen was detected by specific ELISA. Immunoblotting revealed a specific 25 kDa band in patient sera against the responsible Okonomi-yaki mix, which was absorbed by
Der. f. crude antigen.
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