Blue dyes, blue people: the systemic effects of blue dyes when administered via different routes.

We report 4 patients who had facial color changes to a blue-green-gray color and decreased oxygen saturation as measured by pulse oximetry. Patient 1 received an intravenous (IV) methylene blue solution during a urologic procedure, and the remaining three patients were administered subcutaneous indigo carmine (patient 2) or Patent Blue (Patients 3 and 4) for axillary lymph node mapping. All patients had above normal methemoglobin levels. Two (Patients 2 and 3) had hypotension, and one (Patient 3) required IV ephedrine to restore hemodynamic stability. Patient 4 had a hypersensitivity reaction characterized by systemic urticaria and blue-colored subintegumentary edema due to the subcutaneous administration.