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The skin is the largest organ of the human body. An average adult has about two square yards of skin which protects the inside of the body from the outside environment. The skin serves a number of important roles including protecting the tissue of the body from bacteria and viruses and regulating body temperature. It also acts as a sensory organ providing feeling for cold, heat, wet, dry, and movement as air passes across its surface.
The skin can be damaged in a variety of ways, including by being burned. Most burns are caused by heat such as fire, steam, or hot liquids. Serious burns can also be caused by chemicals, electricity, and exposure to the sun. Healthy skin consists of three layers of tissue. Burns are classified based on many of these layers are damaged by the burn.
• First-degree burns – These burns include only the top layer (epidermis) of the skin. Sunburn is often a first degree burn.
• Second-degree burns – These burns extend into the middle layer of the skin (dermis). Second degree burns are often classified as superficial (affecting less of the dermis) or deep (involving more of the thickness of the dermis). Second degree burns often cause blisters.
• Third-degree burns- These burns include all three layers of the skin- the epidermis, dermis, and fat layer. In many cases, other structures in the skin including the sweat glands, hair follicles, and nerve endings are destroyed in third-degree burns. These are typically the least painful burns because the nerve endings have been destroyed and can no longer send pain signals to the brain.
In addition to looking at how deep a burn is doctors classify burns by how severe they are.
All first-degree and some second-degree burns that cover less than 10 percent of the body are considered minor. These burns will heal with little or no treatment. Deeper burns and those burns that cover a larger portion of the body are classified as moderate or severe. These burns often cause complications including fluid seepage out of the burned tissues resulting in dehydration.