title: Type I immediate hypersensitivity reaction to cyanocobalamin but not hydroxycobalamin.
abstract: We report a case of a 42-year-old woman with a background of autoimmune polyglandular syndrome, who developed a type I immediate hypersensitivity reaction to intramuscular cyanocobalamin. Intradermal testing showed a positive reaction to cyanocobalamin. The patient was subsequently treated with intramuscular hydroxycobalamin after negative intradermal testing to this alternative B(12) compound. A review of previously described cases of hypersensitivity to either compound provides a rationale for the management of this rare but serious side-effect.
authors.affiliation: Department of Dermatology, St Vincent's University Hospital, Dublin, Ireland.
authors.forename: F J
authors.initials: FJ
authors.lastname: Moloney
authors.forename: R
authors.initials: R
authors.lastname: Hughes
authors.forename: D
authors.initials: D
authors.lastname: O'Shea
authors.forename: B
authors.initials: B
authors.lastname: Kirby
mesh_terms: D000328:Adult; D000752:Anemia, Pernicious / Q000188:drug therapy; D004342:Drug Hypersensitivity / Q000209:etiology*; D005260:Female; D006801:Humans; D006879:Hydroxocobalamin / Q000008:administration & dosage / Q000009:adverse effects; D006969:Hypersensitivity, Immediate / Q000139:chemically induced*; D007273:Injections, Intramuscular; D016896:Treatment Outcome; D014805:Vitamin B 12 / Q000008:administration & dosage / Q000009:adverse effects*; D014806:Vitamin B 12 Deficiency / Q000188:drug therapy*; D014803:Vitamin B Complex / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D014803:Vitamin B Complex; D014805:Vitamin B 12; D006879:Hydroxocobalamin