An electrical burn is an injury caused by electric current passing through the body, generating heat and damaging tissues along its path. Unlike a flame or chemical burn, the visible wound on the skin often represents only a fraction of the total damage. Internally, electrical current can destroy muscle, nerves, and blood vessels far from the entry and exit points on the skin, making these injuries deceptively dangerous.
How Electrical Burns Differ From Other Burns
A thermal burn from a hot surface or flame damages the skin from the outside in. An electrical burn works differently: current enters the body at one point, travels through internal tissues, and exits at another. Along that path, the current generates intense heat, especially where it meets resistance. Skin has high electrical resistance, so the entry and exit wounds may look like localized burns. But beneath the surface, the current can cook muscle fibers, damage blood vessel walls, and disrupt nerve function across entire limbs or through the torso.
This is why emergency physicians treat electrical burns as “iceberg injuries.” The skin damage you can see is often minor compared to what’s happening deeper inside. A person might have small, unremarkable-looking burns on a hand and foot yet have extensive muscle death throughout an arm or leg. The absence of dramatic external burns does not rule out life-threatening internal damage.
What Happens Inside the Body
Electric current injures tissue through two mechanisms simultaneously. The first is thermal: as current flows through tissue, it generates heat proportional to the resistance it encounters. Bone, tendons, and fat resist current more than muscle and blood vessels do, so heat concentrates unpredictably throughout the body’s interior. The second mechanism is cellular: electrical energy directly disrupts cell membranes, a process called electroporation, which kills cells even in areas that didn’t get hot enough to “cook.”
This combination means tissue destruction continues to evolve after the initial shock. Cells damaged but not immediately killed may die over the following hours and days, causing what physicians call progressive necrosis. It’s one reason electrical injuries are so difficult to assess early on. The full extent of the damage may not become clear for days.
Low Voltage vs. High Voltage
In medical settings, the dividing line between low-voltage and high-voltage electrical injuries is 1,000 volts. Standard household current in the United States runs at 120 or 240 volts, placing it in the low-voltage category. Power lines, industrial equipment, and lightning fall into the high-voltage range.
Both categories can be fatal. High-voltage injuries tend to cause more extensive tissue destruction and are associated with severe muscle death and limb loss. But low-voltage alternating current, the kind running through household wiring, is particularly efficient at triggering fatal heart rhythms. Even a 220-volt domestic shock can cause sudden cardiac arrest if the current passes through the chest.
Heart Rhythm Disruption
The heart runs on its own electrical signaling system, and external current can override it. The most common heart rhythm disturbances after electrical injury are a rapid heart rate and extra heartbeats, but more dangerous rhythms can develop, including atrial fibrillation, ventricular tachycardia, and ventricular fibrillation (which is cardiac arrest).
These rhythm problems don’t always appear immediately. In documented cases, dangerous arrhythmias have developed 8 to 12 hours after the shock, even in people who initially seemed stable. This is why hospitals typically monitor the heart for at least 24 hours after a significant electrical injury. Someone with a low-voltage injury, no loss of consciousness, and a normal initial heart tracing may be cleared sooner, but anyone whose current path crossed the chest needs close observation.
Muscle Breakdown and Kidney Damage
When electrical current destroys muscle tissue, the contents of those cells spill into the bloodstream. This condition, called rhabdomyolysis, floods the body with proteins and enzymes that the kidneys must filter out. One protein in particular, myoglobin, can physically clog the tiny filtering tubes inside the kidneys. When enough muscle is damaged, the volume of myoglobin overwhelms the kidneys’ capacity, potentially causing kidney failure.
A visible sign of this process is dark, tea-colored urine, caused by myoglobin being excreted. If you or someone else notices this after an electrical injury, it’s a red flag that significant muscle breakdown is occurring. Aggressive fluid treatment in the hospital is the primary way to protect the kidneys by flushing myoglobin through before it can accumulate and cause blockages.
Electrical injuries to arms or legs carry an additional risk: compartment syndrome. As damaged muscles swell within the tight tissue sheaths that surround them, pressure builds with nowhere to go. This rising pressure can cut off blood flow to the limb entirely, requiring emergency surgery to release the pressure before the tissue dies from oxygen deprivation.
Neurological Effects, Immediate and Delayed
Nerve damage at the entry and exit sites of the current is extremely common. But electrical injuries can also affect the brain and spinal cord, producing a wide range of neurological symptoms. In the short term, people may experience numbness, weakness, memory loss, headaches, dizziness, and difficulty with coordination.
What makes the neurological picture especially tricky is that symptoms can appear long after the injury itself. Research has documented new neurological problems emerging anywhere from days to five or more years after the electrical event. These delayed symptoms include chronic pain, tremor, seizure disorders, poor concentration, difficulty with verbal learning, ringing in the ears, and loss of balance. Neurological symptoms that appear immediately after the injury tend to have a better recovery outlook than those with a delayed onset, which may reflect ongoing cellular damage that wasn’t apparent at first.
Immediate Safety and First Aid
The first priority with any electrical injury is making sure the current source is no longer a threat. If you witness someone being shocked, do not touch them while they’re still in contact with the electrical source. Turn off the power if you can. If you can’t, use a dry, non-conducting object (cardboard, plastic, a wooden board) to separate the person from the source. Stay at least 50 feet away from downed power lines, and if a live wire contacts a vehicle you’re in, stay inside until the power is disabled.
Once the scene is safe and emergency services are on the way, check for breathing and a pulse. If neither is present, begin CPR. Cover visible burns with sterile gauze or a clean cloth, but don’t try to clean the wound or remove stuck clothing. Avoid using blankets or towels directly on burn areas, as loose fibers can embed in the wound.
Any electrical injury that involved current passing through the body (as opposed to a superficial flash or arc burn to the skin) warrants emergency evaluation, even if the person feels fine. The combination of hidden internal damage, delayed heart rhythm changes, and progressive tissue death means that what looks like a minor injury can escalate hours later. Hospital evaluation typically includes heart monitoring, blood tests to check for muscle breakdown, and assessment of the limbs for compartment syndrome.