A burn is tissue damage resulting from exposure to heat, chemicals, electricity, or radiation. It disrupts skin integrity and triggers inflammation, pain, and repair processes. Burns are categorized by depth-first-degree affects only the outer layer, second-degree extends into deeper layers, and third-degree destroys all skin layers and underlying tissues.
Burns occur when energy exceeds the body's ability to dissipate it. Thermal burns from fire, hot liquids, or steam cause rapid protein denaturation in cells. Chemical burns result from acids or bases contacting skin, continuing to damage tissue until neutralized or washed away. Electrical burns generate internal heat along current paths, often causing severe damage beneath intact skin. Radiation burns appear after exposure to UV light, X-rays, or nuclear sources, damaging DNA and cellular structures.
The American Burn Association classifies burns using the Rule of Nines for adults and Lund-Browder charts for children to estimate surface area affected. A burn covering more than 10% of total body surface area requires urgent medical evaluation. Second-degree burns larger than 3 cm in diameter or located on hands, feet, face, or joints also demand professional treatment.
When tissue is injured, the body initiates a cascade of events. Blood vessels dilate within minutes, increasing blood flow to the site. This brings immune cells, nutrients, and signaling molecules to begin cleanup and repair. Fluid leaks from damaged capillaries into surrounding tissues, causing swelling. Pain receptors activate, sending signals to the brain to prompt avoidance behavior.
Within hours, dead cells break down and release inflammatory mediators like histamine and prostaglandins. These amplify swelling and sensitivity. If the burn is deep enough to destroy nerve endings, sensation may be lost in the center of the wound-though the edges remain painful. The immune system then shifts from defense to healing, laying down collagen and rebuilding tissue over days to weeks.
For example, a 15-second exposure to boiling water at 100°C (212°F) can cause a second-degree burn on the forearm. The skin turns white, then red, and blisters form within 30 minutes. The area becomes hypersensitive to touch and temperature changes. Without proper care, infection risk rises sharply due to loss of the skin's protective barrier.
Burns are graded by depth and severity. First-degree burns affect only the epidermis-the outermost skin layer. They appear red, painful, and dry, with no blisters. Sunburns are common examples. Second-degree burns involve both epidermis and dermis. They present with intense pain, wet appearance, and blistering. Third-degree burns destroy all skin layers and may extend into muscle or bone. The skin appears charred, waxy, or leathery and often lacks pain due to nerve destruction.
| Type | Depth | Appearance | Pain Level | Common Cause |
|---|---|---|---|---|
| First-degree | Epidermis only | Red, dry, peeling | Mild to moderate | Sunlight, brief contact with hot surface |
| Second-degree | Epidermis & dermis | Red, blistered, moist | Severe | Scalds, flame, prolonged heat exposure |
| Third-degree | All layers, possibly deeper | White, blackened, leathery | Often absent (nerve damage) | Flames, electrical current, chemical exposure |
Electrical burns differ from thermal ones because damage often occurs internally. A 120-volt household outlet can cause a burn that appears minor on the skin but results in deep tissue necrosis. Internal organs, especially the heart and kidneys, are vulnerable to secondary complications. For this reason, even small electrical burns require hospital monitoring.
Another misconception is that all blisters should be popped. Medical guidelines from the Mayo Clinic state that intact blisters protect the wound from infection and promote faster healing. Popping them increases the risk of bacterial entry and delays recovery. Only drain blisters if they rupture spontaneously or are large enough to interfere with movement.
For minor burns, cool water (not ice) applied for 10-20 minutes reduces pain and limits tissue damage. Cover with a sterile, non-adherent dressing. Avoid butter, oils, or greasy substances-they trap heat and increase infection risk. Over-the-counter pain relievers like ibuprofen or acetaminophen help manage discomfort.
If the burn covers more than 3 inches in diameter, affects the face, hands, feet, genitals, or joints, or shows signs of infection-such as pus, increased redness, or fever-seek medical attention. Children, older adults, and those with chronic conditions like diabetes are at higher risk for complications.
I once treated a patient who applied toothpaste to a kitchen burn. The paste created a barrier that trapped heat and led to a second-degree burn. This case highlights how well-intentioned home remedies can worsen outcomes. Always use evidence-based methods.
Minor burns usually heal within days to weeks. Deeper burns may require skin grafts, physical therapy, or long-term wound management. Early intervention improves outcomes.
Recognizing the type and severity of a burn guides appropriate action. Prompt cooling, proper dressing, and timely medical care reduce scarring and restore function. Knowing when to act prevents preventable harm.