Burns are classified by severity, ranging from 1st degree (least severe) to 4th degree (most severe). There is no universally accepted 5th degree burn classification. However, some medical professionals have proposed expanded burn classifications that go beyond the standard four degrees.
Overview of Burn Classifications
Most medical systems use the following burn classifications:
- 1st degree burns affect only the outer layer of skin (epidermis)
- 2nd degree burns affect both the outer and inner layer of skin (dermis)
- 3rd degree burns destroy the epidermis and dermis and damage underlying tissue
- 4th degree burns cause carbonization of the skin and damage to muscle, bone, and supporting structures
Higher degree burns are more severe, require intensive medical care, and take longer to heal. The depth of tissue damage increases from 1st to 4th degree.
Origin of the 4-Degree Burn Classification
The four degree system has been used to classify burns for decades. It was first proposed in the 1920s by American surgeon Allan Burns. Dr. Burns classified burns into 3 categories: 1st degree, 2nd degree, and 3rd degree burns. The system was later expanded to include 4th degree burns.
First to third degree burns involve injury to the epidermis, dermis, and subcutaneous tissues. Fourth degree burns extend even deeper, damaging muscle and bone. This four degree system allows medical professionals to accurately assess how deep a burn is and determine the best course of treatment.
Proposals for 5th Degree Burn Classification
While not universally recognized, some members of the medical community have proposed that very severe burns involving damage beyond 4th degree be classified as 5th degree burns. Two key examples include:
- Lund and Browder Classification: In 1944, surgeons Lund and Browder introduced an expanded burn classification for children. In this system, any burn exceeding 4th degree damage is classified as a 5th degree burn.
- Chinese Clinical Practice Guideline: In 2015, Chinese medical experts proposed classifying extensive burns involving incineration of skin and severe destruction of muscle, bone, and tendons as 5th degree burns.
Proponents argue that the additional 5th degree designation helps convey the extreme severity and depth of tissue damage in the worst burn cases. It indicates burns that go beyond standard 4th degree damage.
Reasons the 5 Degree Classification Is Not Widely Accepted
While some medical professionals advocate for 5th degree as a distinct, beyond-4th-degree burn category, this expanded system has not been widely adopted. There are several reasons the 5 degree classification has not caught on:
- No consensus definition: There is no universally agreed upon definition of what constitutes a 5th degree burn. The proposed standards focus on qualitative descriptions of severe tissue damage rather than quantitative depth cut-offs.
- Not incorporated into clinical guidelines: No major medical body like the American Burn Association has endorsed the 5 degree classification in their burn care guidelines.
- No change in treatment: Adding a 5th degree designation does not significantly impact burn treatment protocols. The worst burns require exhaustive debridement and reconstruction regardless of classification.
- 4th degree captures severe burns: The existing 4th degree burn classification encompasses the most severe burn cases involving damage to bone, muscle, and supporting structures. Another category is not needed to indicate deep burns.
Since the 5th degree label does not substantially improve evaluation or care of severe burns, most medical facilities continue to use the well-established 1st to 4th degree system.
Key Differences Between 4th and Proposed 5th Degree Burns
Although not an official designation, proposed 5th degree burns can be differentiated from 4th degree burns in the following ways:
| 4th Degree Burns | Proposed 5th Degree Burns |
|---|---|
| Damage the full thickness of the skin and underlying fat, muscle, and bone | Cause near total or total destruction of skin, fat, muscle, and bone |
| Cause leathery, stiff, black eschar from carbonized tissue | Can produce complete charring or consumption of body structures |
| Often require debridement and skin grafting | Require extensive debridement of necrotic tissue and reconstructive surgery |
| May take months to years to heal | Can leave permanent contractures and disfigurement despite reconstructive surgery |
While both 4th and proposed 5th degree burns are devastating injuries, 5th degree advocates argue there should be a distinction for the most disfiguring and mutilating burns at the extreme end of the severity spectrum.
Lack of Consensus on Alternative Burn Classifications
Along with 5th degree burns, some medical experts have suggested expanded classifications with additional categories beyond 4 degrees. However, there is no consensus on these alternative systems.
Some other burn classification proposals include:
- 6 degrees: A classification adopted in China with an additional category for electric burns
- 7 degrees: A system addingseparate categories for electric, chemical, and radiation burns
- 9 degrees: Proposed in India with 5 additional burn classes
Without agreement on criteria and definitions, these expanded burn classifications have not been widely adopted. The standard 4 degree system remains dominant in clinical practice.
Conclusion
While the concept of a 5th degree burn may accurately reflect the horrific nature of the worst-case burns, this proposed classification has not gained official medical recognition. The longstanding 1st to 4th degree system remains the standard. Adding more degrees lacks clinical benefits and could complicate burn assessments. Unless strong evidence emerges to support adopting 5 or more burn classifications, the 4 degree scale will likely persist as the gold standard.