Hypersensitivity reaction to Patent Blue Dye

Patent Blue Dye (PBD) is a synthetic blue dye commonly used in medical practice for sentinel lymph node mapping in breast cancer. The authors report the case of a patient with invasive ductal carcinoma of the left breast, who underwent unilateral mastectomy with sentinel lymph node mapping. During surgery, the patient developed violaceous urticaria and mild glottic edema. A hypersensitivity reaction to PBD was confirmed by skin prick tests and methylene blue was identified as a possible alternative dye. This article reinforces the need for greater awareness of the possible hypersensitivity reactions to PBD during surgical procedures.