A burn is damage to the tissue due to heat, fire, chemicals, electricity, sunlight, radiation, or steam from liquids or gases.
Burns are classified as follows:
- Superficial skin burns injure the first layer of skin. A non-blistering sunburn is an example.
- Superficial partial-thickness burns injure the first and second layers of the skin. A blistering sunburn is an example.
- Deep partial-thickness burns extend even deeper into the skin.
- Full-thickness burns injure all layers of the skin and damage tissues under the skin, including muscles, ligaments, tendons, nerves, and blood vessels.