A case of hypersensitivity reaction to enokitake (flammulina velutipes) ingestion

We experienced a case of 10-year-old girl who developed hypersensitivity reactions after eating enokitake. The patient had food allergy to egg until5 years old. When she was 4 years old, she ate enokitake with a hot-pot dish. Later, she felt itching in her mouth. Therefore, she never ate enokitake since that time. At the age of10, she drank only the soup of enokitake with school lunch. After that she felt discomfort and itching in her oral cavity. The result of enokitake and other mushrooms (siitake, simeji, and eringi) skin prick to prick test were all positive. We performed Western blotting with enokitake extracts and the patient's serum. Enokitake protein s band (75kDa) reacted specifically with the patient's IgE. At the same time Western blotting was performed with the patient's serum of previously reported enokitake anaphylaxis, but a 75kDa band showing specific reaction in this case was not observed. This band we identified was a novel enokitake allergen.