A 35-year-old female, professional diver, reported nausea, vomiting, and systemic hives 20 to 30 minutes after ingestion of antipasto made with jellyfish. Patient reported prior episodes of swelling after stings from several different creatures, including jelly fish. She also developed a systemic allergic reaction after sting from an unknown creature while diving. On the initial visit to our hospital, serum total IgE level was 545IU/ml. We extracted crude allergen from jellyfish and evaluated allergen specific IgE antibody levels using ELISA. Patient samples showed higher levels of jellyfish-derived allergen specific IgE than healthy control samples. Basophils were isolated from the peripheral blood of patient. Stimulation with jellyfish-derived allergen showed expression of surface antigens on basophils increased in a concentration-dependent manner. Methods using sodium dodecyl sulfate poly acrylamide gel electrophoresis and immunoblotting showed acid-soluble collagen fraction from jellyfish contained above 250kDa weighed protein that may have caused this current event. A provocation test using jellyfish samples was not performed due to risk of anaphylactic shock. The patient was diagnosed with a jellyfish allergy due to IgE mediated anaphylaxis after ingestion. She was asked to refrain from consuming any food containing jellyfish. IgE-mediated food allergy caused by jellyfish is rare worldwide. Collagen was speculated to be an allergen in this study. Additional study to detect specific allergens related to jellyfish allergy would be particularly useful to specify disease phenotypes and individual care in future.

We report a case of jellyfish allergy diagnosed via an oral food challenge. A 14-year-old boy had no history of jellyfish stings and had been eating commercially available jellyfish products twice yearly for the past 5-6 years. Five minutes after eating a commercially available boiled jellyfish product (100g), he experienced nausea, wheezing, and erythema and had visited our hospital. We suspected an anaphylactic reaction and treated him with intramuscular adrenaline injection, corticosteroid and antihistamine infusions, volume resuscitation, and salbutamol sulfate inhalation, which resulted in an improvement of the symptoms. One-month later in our hospital, we administered an oral food challenge of the same boiled jellyfish product bought at the same grocery store to the patient. After ingesting 14g of boiled jellyfish, he experienced erythema, wheezing, nausea, and abdominal pain. Several reports have described anaphylaxis caused by the ingestion of jellyfish, but the allergens in jellyfish have not been analyzed. A skin prick test for poly-gamma-glutamic acid (PGA) which is a component of jellyfish stings was negative. This suggests that he was sensitized to some allergen other than PGA via a route different from that of jellyfish sting. Our skin prick test for several kinds of edible jellyfish suggests that allergenicity may be different for different jellyfish.