What Is a Fourth-Degree Burn?

A fourth-degree burn is the most serious type of burn possible to sustain. Burns are classified in a rating system from first to fourth, with fourth being the worst. These burns are often caused by electrical fires, chemicals or extended contact with flames, and they are characterized by significant damage to the skin, muscles, ligaments and bones. Such burns can be life threatening and require extended periods of rehabilitation and therapy.

When a fourth-degree burn is sustained, the major tissues of the skin and underlying layers are completely destroyed. These burns are not painful after the event because the damaged sensory nerves can no longer send pain signals to the brain. Layers of skin, muscles, tendons, ligaments and possibly bone are eradicated, and the burn site will be deep. The burn area will be black in appearance, and eschar will develop as healing occurs. Eschar is layers of dead skin and tissue like a scab that falls off gradually from the burn.

Surgical treatment is always necessary for a fourth-degree burn. The area may need to be grafted to close up the site and prevent infection, but sometimes a skin graft is not possible with this severity of burn. In many cases, it is impossible to repair the area or save the limb, but amputation may be necessary to save the patient's life. Regardless of the treatment required, patients will typically experience significant impairments in daily living skills and will require months to years of rehabilitation and therapy.

Rehabilitation after a fourth-degree burn will involve a number of different types of therapy including physical, occupational and psychological services. Physical therapy will assist with gross motor tasks, such as walking or using the upper extremities again, while occupational will address daily living and self-help skills like cooking, cleaning, dressing and bathing. Psychological therapies address the emotional aftermath of burn trauma and, perhaps, the adjustment to a new body or scars.

The likelihood of fatality resulting from a serious burn depends on the percentage of the body burned, the age of the patient, overall health and other associated injuries. Death risks rise with the amount of the body that is burned, particularly in key areas like the head and chest. Older people are more likely than younger people to die as a result of a fourth-degree burn, and young children will require more fluid support and specialized treatment than adults.