Electrothermal ring burn from a car battery.

Despite prevention efforts, burn injuries among auto mechanics are described in the literature. Electrothermal ring burns from car batteries occur by short-circuiting through the ring when it touches the open terminal or metal housing. This article describes a 34-year-old male auto mechanic who was holding a wrench when his gold ring touched the positive terminal of a 12-volt car battery and the wrench touched both his ring and the negative terminal. He felt instant pain and had a deep partial-thickness circumferential burn at the base of his ring finger. No other soft tissues were injured. He was initially managed conservatively, but after minimal healing at 3 weeks, he underwent a full-thickness skin graft. The graft incorporated well and healed by 4 weeks postoperatively. He had full range of motion. The cause of ring burns has been controversial, but based on reports similar to the current patient's mechanism, they are most likely electrothermal burns. Gold, a metal with high thermal conductivity, can heat up to its melting point in a matter of seconds. Many treatments have been described, including local wound care to split- and full-thickness skin grafts. Because most burns are preventable, staff should be warned and trained about the potential risks of contact burns. All jewelry should be removed, and the live battery terminal should be covered while working in the vicinity of the battery.