Full-thickness burns, also known as third- and fourth-degree burns, represent the most severe form of burn injuries, involving the complete destruction of the epidermis and dermis, and often extending into the subcutaneous tissues. These injuries pose significant challenges in wound care due to their complexity and potential for severe complications.
Thickness and depth. Full-thickness burns extend through the skin into underlying tissues, potentially including fascia, muscle, and bone.1,2
Appearance. Blackened and charred with eschar formation. Eschar may be pale or dark.1,2
Sensation. Painless due to extensive nerve destruction.1,2
Texture. Dry and necrotic.1,2
Healing and prognosis. Full-thickness burns do not heal spontaneously and may necessitate amputation or extensive reconstructive surgery in severe cases. They are associated with significant functional impairment and can be life-threatening.1,2
Another contributing factor to burn severity is how much of the body is affected. The "rule of nines" is a method of approximation used to determine what percentage of the body is burned.3 Partial- or full-thickness burns on more than 15% of the body require immediate professional medical attention. Use the following approximations for adults:
• Head (front and back) ~ 9%
• Front of the torso ~ 18%
• Back of the torso ~ 18%
• Each leg (front and back) ~ 18%
• Each arm (front and back) ~ 9%
• Genitals/perineum ~ 1%
Additionally, the patient’s palm (including the fingers) is approximately 1% of the total surface area of the body, and can be used to approximate noncontiguous burn areas.
Several factors increase the likelihood of sustaining full-thickness burns, similar to the risk factors for burns in general:
Age. Young children and older adults are at increased risk due to thinner skin and reduced reaction times.4
Occupational hazards. Jobs involving exposure to hot substances, open flames, or chemicals elevate the risk of burns.4
Environmental factors. High ambient temperatures, inadequate protective measures, and unsafe cooking practices contribute to burn incidents.4
Medical conditions. Individuals with sensory impairments or mobility limitations may be more susceptible to accidental burns.4
Full-thickness burns can result from various mechanisms:
Thermal. Caused by fire, hot objects, steam or hot liquids (scalding).3
Electrical. Caused by contact with electrical sources or, in much more rare circumstances, by lightning strike.3
Chemical. Caused by contact with highly acidic or basic substances.3
Radiation burns. Exposure to high doses of radiation, such as from industrial accidents or radiation therapy, can lead to full-thickness burns.3
Friction. Caused by friction between the skin and hard surfaces, such as roads, carpets or floors.3
Management of full-thickness burns aims to promote healing, prevent infection, and minimize complications:
Initial assessment. Follow the Airway, Breathing, Circulation (ABCs) to ensure airway patency, adequate breathing, and circulation.3 Determine the total body surface area (TBSA) affected and the depth of the burn to guide treatment decisions.
Wound care. Gently clean the burn wound with mild soap and water or saline to remove debris and reduce the risk of infection. Remove necrotic tissue to promote healing and prepare the wound bed for potential grafting.5 Debride ruptured blisters to prevent infection; small intact blisters may be left in place or aspirated based on clinical judgment.
Dressings. Apply topical antimicrobial agents to reduce microbial colonization.6 Use hydrocolloid or foam dressings to maintain a moist environment conducive to healing.7
Pain management. Administer appropriate analgesia, including non-opioid and opioid medications, to manage pain effectively.3
Surgical intervention. Consider surgical removal of necrotic tissue followed by skin grafting to expedite healing and reduce scarring.5
Infection control. Regularly assess for signs of infection, including increased redness, swelling, or purulent discharge.8 Initiate systemic antibiotics only if clinical infection is suspected or confirmed.
Rehabilitation. Implement physical therapy exercises to maintain joint mobility and prevent contractures. Occupational therapy can help patients in regaining functional abilities and adapting to any limitations.
Infection. Disruption of the skin barrier increases the risk of bacterial invasion, potentially leading to cellulitis or sepsis.3
Scarring and contractures. Delayed healing can result in hypertrophic scarring and joint contractures, impairing function and appearance.3
Systemic complications. Extensive burns may lead to hypovolemia, hypothermia, or metabolic disturbances, necessitating comprehensive supportive care.9
References
1. Warby R, Maani CV. Burn Classification. [Updated 2023 Sep 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK539773/
2. American Burn Association. Guidelines for Burn Patient Referral. Available at https://ameriburn.org/wp-content/uploads/2024/04/one-page-guidelines-fo…. Published 2022. Accessed March 21, 2025.
3. Żwierełło W, Piorun K, Skórka-Majewicz M, Maruszewska A, Antoniewski J, Gutowska I. Burns: classification, pathophysiology, and treatment: a review. Int J Mol Sci. 2023;24(4):3749. Published 2023 Feb 13. doi:10.3390/ijms24043749
4. World Health Organization. Burns. Available at https://www.who.int/news-room/fact-sheets/detail/burns. Published Oct. 13, 2023. Accessed March 21, 2025.
5. Anyanwu JA, Cindass R. Burn Debridement, Grafting, and Reconstruction. [Updated 2023 May 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK551717/
6. Norman G, Christie J, Liu Z, et al. Antiseptics for burns. Cochrane Database Syst Rev. 2017;7(7):CD011821. Published 2017 Jul 12. doi:10.1002/14651858.CD011821.pub2
7. Wasiak J, Cleland H, Campbell F. Dressings for superficial and partial thickness burns. Cochrane Database Syst Rev 2008; :CD002106.
8. Gauglitz GG, Shahrokhi S, Williams FN. Burn wound infection and sepsis. UptoDate. Available at https://www.uptodate.com/contents/burn-wound-infection-and-sepsis. Updated March 18, 2025. Accessed March 21, 2025.
9. Schaefer TJ, Tannan SC. Thermal Burns. [Updated 2023 May 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK430773/