RESUMEN
A woman in her 20s presented to our clinic with a lower gastrointestinal infection. When we administered intravenous antibacterial and vitamin infusions, she developed anaphylaxis. We performed skin tests to investigate the cause, and an intradermal test was positive for a 1% intravenous vitamin complex. We then performed a component-specific test, which was positive for thiamine disulfide phosphate, a vitamin B1 derivative. We therefore diagnosed anaphylaxis due to thiamine disulfide phosphate. No previous reports have described cross-reactivity between vitamin B1 derivatives. In our case, however, the patient tested positive for fluthiamine hydrochloride, suggesting cross-reactivity. Intravenous vitamin complexes are used in daily clinical practice and should be administered with caution because of the possibility of anaphylaxis, although it occurs infrequently.