Burns

Burns: Classification and Tissue Damage Mechanism

A burn is damage to body tissues caused by high temperature (thermal burn), chemicals (chemical burn), electric current (electrical burn) or radiation energy. The severity of a burn depends on the depth of tissue damage and the area of the affected surface. Even small but deep burns can be dangerous because of the risk of infection and scar formation.

What happens in the skin during a thermal burn?

Exposure to high temperature leads to denaturation (destruction) of proteins, which are the basis of cells. This causes death of skin cells. In response to the injury, the body initiates an acute inflammatory reaction: blood vessels dilate, their permeability increases, leading to plasma leakage into tissues, forming edema and blisters. Damage to nerve endings causes intense pain.

Burn Degrees (by depth of injury)

• First degree: Damage only to the superficial layer of the skin (epidermis). Characterized by redness, swelling and pain. A classic example is a sunburn. Heals on its own without scarring.
• Second degree: Damage to the epidermis and the upper layers of the dermis. A characteristic sign is the formation of blisters filled with clear or yellowish fluid. Burns of this degree are very painful. They heal on their own but may leave pigmentation.
• Third degree: Damage to all layers of the skin, including the subcutaneous tissue. A scab (dry crust) forms. Pain sensitivity may be reduced due to nerve ending destruction. Healing occurs with the formation of coarse scars. Often requires surgical treatment.
• Fourth degree: The most severe level, in which tissue carbonization occurs, along with damage to muscles, tendons and bones.

Assessing the burn surface area is critically important for determining the treatment strategy. Even first‑ and second‑degree burns, if they cover a large area, can be life‑threatening because of the risk of dehydration and infection. All burns, except minor superficial ones, require a medical examination. After healing, it is important to protect the affected area from sunlight to avoid hyperpigmentation.