Burns are classified as first-, second-, or third-degree, depending on how deep and severe they penetrate the skin's surface.
First-degree (superficial) burns
First-degree burns affect only the epidermis, or outer layer of skin. The burn site is red, painful, dry, and with no blisters. Mild sunburn is an example. Long-term tissue damage is rare and usually consists of an increase or decrease in the skin color.
Second-degree (partial thickness) burns
Second-degree burns involve the epidermis and part of the dermis layer of skin. The burn site appears red, blistered, and may be swollen and painful.
Third-degree (full thickness) burns
Third-degree burns destroy the epidermis and dermis and may go into the subcutaneous tissue. The burn site may appear white or charred
Fourth degree burns. Fourth degree burns also damage the underlying bones, muscles, and tendons. There is no sensation in the area since the nerve endings are destroyed..