First Degree Burn: Involves only the epidermis. It causes redness, mild pain, but there is no blistering. A sun-burn is a good example of a 1st degree burn.
Second Degree Burn (partial-thickness burn): Involves the epidermis and part of the dermis. Blister formation with fluid accumulation are classic signs. Blisters are formed when the epidermis seperates from the dermis because of fluid accumulation between these layers. Accessory structures such as hair follicles, and sebacious and sudoriferous glands are usually not damaged. These burns may take 3-4 weeks to heal.
Third Degree Burn (full-thickness burn): These burns destroy the epidermis, dermis, and subcutaneous layers with the loss of most skin functions. They may appear marble-white to mahogany to charred, dry wounds. Because sensory nerves have been destroyed, the area is numb with marked edema.