Time-Lapse Video Visualizing Hyperhidrosis With Water-Erasable Ink

Frey syndrome is characterized by abnormal flushing and hyperhidrosis of the face that occurs while eating—a phenomenon termed gustatory sweating—that typically arises due to trauma to the auriculotemporal nerve. This time-lapse video (×5 speed) demonstrates the dissolution of water-erasable ink with gustatory sweating to delineate the affected area for treatment with botulinum toxin injections. A grid was drawn on the affected side of the face, and the patient was asked to eat provocative foods for 5 minutes. As gustatory hyperhidrosis emerged, a focal region of the grid gradually vanished to indicate the affected area. After 5 minutes, the affected area was physically outlined in preparation for treatment.