Thermal burns, or burns caused by heat, come in several degrees of severity. There are several different classification systems used to categorize thermal burns, using the depth of tissue involvement as a landmark for determining how serious a burn is. Burn patients should be aware that staging a burn can involve some invasive investigation on the part of the medical team, and that this can be extremely painful, but it is important to make sure that the burns are treated properly.
Some medical professionals use a “degree” system, breaking thermal burns into first, second, and third degree burns, with a rarer fourth degree burn category being seen in some regions. Others categorize thermal burns as superficial, partial thickness, or full thickness burns. Sometimes, partial thickness burns are divided into superficial and deep, creating four possible categories.
First degree or superficial thermal burns are the least serious. They involve the upper layer of skin, known as the epidermis, and they are characterized by redness and light blistering. Often, these burns will heal completely without leaving a scar, and they pose a low risk of infection. Treatment can usually be performed at home.
Second or partial thickness burns are more serious. These burns are sometimes divided into second/third degree and superficial partial thickness/deep partial thickness, as discussed above. They involve the deeper layer of skin, known as the dermis, although sweat glands and hair follicles are usually left intact. The skin will blister, and it typically turns very red and it may weep bodily fluids like lymph. These burns can sometimes be treated at home, but medical attention is advised, because they are at risk of edema and infection which can create complications.
Third degree burns, known as fourth degree burns in a four degree burn system or as full thickness burns involve deep layers of tissue. The sweat glands and hair follicles are destroyed, and the tissue may be charred or it can acquire a blanched white color. The burn itself does not hurt, because there are no nerve endings left, but it may be surrounded with an extremely painful partial thickness burn. These types of burns usually require grafts for recovery, and the patient needs to be treated in a burn unit, because he or she is very vulnerable to infections which could turn deadly.
The extent of thermal burns is also an important issue when these burns are classified by a medical team. Doctors often use a tool known as the “rule of nines,” in which the body is divided into 11 sections, each of which comprises roughly nine percent of the total surface area, to determine the extent of a burn, with the genitals accounting for the remaining one percent. Burns over more that 50% of the body are extremely dangerous.