A case of pediatric anaphylaxis caused by gummy tablets containing fish collagen.

Fish collagen is one of the major allergens involved in fish allergies; however, it has not been well-established whether fish collagen can cause anaphylaxis among individuals with fish allergies, especially children. A 9-year-old girl experienced anaphylaxis after consuming 2 fruit-flavored gummy tablets. Contacting the manufacturing company revealed that fish-derived collagen was used in the gummy tablets, and an oral fish collagen challenge test confirmed that the anaphylaxis was induced by fish collagen. Immunoblot analysis showed a 120-kDa band in a sample of the fish collagen in the gummy tablets, and no reactive band of the pork gelatin was observed. Additionally, salmon collagen and other fish samples that provoked symptoms were detected as a 120-kDa band in the immunoblot analysis. The 120-kDa band was identified as fish collagen by mass spectrometry confirming that it was the causative antigen of our patient's allergy. This case study confirms that fish collagen can cause anaphylaxis in children with fish allergies. Physicians and allergic individuals need to be aware that processed foods may contain fish collagen to avoid allergic reactions.