Anaphylactic shock perioperative to patent blue dye.

Patent blue is one of the most used dyes for the identification of sentinel lymph nodes in breast cancer. This report describes a case of an anaphylactic shock reaction to patent blue dye in a patient with cross-reactivity to methylene blue. Therefore, after allergy confirmation, the operation was repeated avoiding blue dye and an alternative labelling technique with 99mTc albumin nanocolloids was used.