Burns can be classified in several ways depending on the depth and amount of tissue that is involved. First degree burns are the least severe. They are usually shallow, only affect the top layer of skin, and can be red and painful. Second degree burns are more severe involving the two outer layers of skin (epidermis and dermis), they blister, and can have varying amounts of pain depending on whether or not nerves were also damaged. Third degree burns char or blacken the skin. They are usually not painful because nerves are completely damaged. Fourth degree burns can injure deeper tissues like muscles, tendons and bones. Usually, fourth degree burns will result in the loss of the affected area. Treatment for a burn first includes figuring out what caused the burn and stopping the burning if necessary. The area is then treated to prevent infection, restore function, and avoid deformity. If cared for properly, less severe burns are not fatal.