A full thickness wound (FTW) represents a severe form of tissue damage that penetrates completely through all layers of the skin. Unlike minor scrapes or cuts, these injuries are characterized by extensive loss of tissue volume. They are incapable of healing simply by the skin’s outer layers regenerating. This profound level of injury requires an organized biological response to repair the defect, rather than restoring the original tissue structure. Due to their depth and complexity, full thickness wounds demand immediate and specialized medical care to manage potential complications and guide the long-term healing process.
Anatomical Scope and Characteristics
A full thickness wound is defined by its penetration past the epidermis and dermis, extending into the subcutaneous layer (hypodermis). When both the outer protective epidermis and the dermis (which contains blood vessels and nerves) are destroyed, the injury reaches the hypodermis, which is primarily composed of adipose, or fat, tissue. The depth of these wounds distinguishes them from partial thickness injuries, which only involve the epidermis and a portion of the dermis. In severe cases, a full thickness injury can extend deeper, exposing underlying structures such as fascia, muscle, tendon, or bone. A lack of sensation within the wound bed is common because the sensory nerve endings in the dermis have been destroyed. The exposed tissue may appear pale yellow (fat), red (muscle), or white (tendon/bone), and the wound edges often show signs of non-viable tissue like dried, dark eschar or moist, yellow slough.
Common Causes of These Injuries
Full thickness wounds result from mechanisms that cause significant tissue destruction, often involving prolonged or intense force. Severe burns, specifically third- and fourth-degree burns, are a frequent cause, as the heat energy completely destroys the skin and underlying tissues. The prolonged application of pressure or shear forces in immobile individuals leads to Stage 3 or 4 pressure injuries, which are examples of full thickness tissue loss. Chronic conditions that impair blood flow or sensation also frequently result in these deep injuries. For example, diabetic foot ulcers can progress to full thickness wounds due to compromised circulation and nerve damage, preventing the patient from sensing and relieving pressure. High-energy trauma, such as deep lacerations from accidents, penetrating injuries, or severe surgical wounds, can also create a defect that bypasses all skin layers.
The Biological Phases of Healing
The body’s repair of a full thickness wound proceeds through an organized, sequential process of overlapping phases. Because the wound cannot pull its edges together for closure, it must heal by a mechanism known as secondary intention, building new tissue from the base upward. The initial phase is Hemostasis, where blood vessels constrict and platelets aggregate to form a clot, followed immediately by the Inflammation phase. During inflammation, white blood cells arrive to clean the wound bed by removing foreign debris and damaged cells, which is necessary before reconstruction can begin. The proliferative phase begins shortly after, centered around the formation of granulation tissue, a new, beefy-red tissue composed of new blood vessels and collagen fibers. Specialized cells called fibroblasts synthesize this collagen, effectively filling the deep void created by the injury. Wound contraction is a parallel process where myofibroblasts pull the edges of the defect inward, reducing the overall size of the open area. Finally, the Maturation and Remodeling phase can last for months or even years, as the newly formed scar tissue is reorganized and strengthened with a more durable type of collagen.
Clinical Management and Treatment Strategies
Managing a full thickness wound centers on creating an optimal environment to support secondary intention healing. The initial and often repeated step is debridement, which is the removal of all non-viable tissue, such as necrotic slough or eschar, until only healthy, bleeding tissue remains. This action is necessary because dead tissue harbors bacteria and physically obstructs the formation of new granulation tissue. Maintaining an appropriate moisture balance is also important, as a wound bed that is too dry will delay cell migration, while excessive moisture can damage the surrounding healthy skin. Clinicians use various advanced dressings, such as hydrogels, alginates, or foam dressings, to absorb excess fluid while keeping the wound surface moist. Infection control often requires systemic antibiotics or specialized topical agents to manage the high risk of bacterial colonization. For large or complex full thickness wounds, surgical intervention is often required; a skin graft or flap procedure may be necessary to rapidly cover the defect and prevent excessive scar formation.
Preventing Complications and Long-Term Care
Due to the depth of tissue destruction, full thickness wounds carry a significant risk of complications that can hinder recovery. Infection poses a threat, as pathogens can easily penetrate deep into the body, potentially leading to systemic infection or osteomyelitis (infection of the underlying bone). The extensive tissue loss and subsequent healing by secondary intention frequently result in the formation of significant scar tissue. This scarring can manifest as hypertrophic scars or keloids, which are raised, thick, and sometimes painful areas of excessive collagen deposition. Functional loss can occur if the scar tissue forms over a joint, leading to a contracture that restricts movement. Long-term care involves monitoring the healed area for changes and engaging in scar management techniques, such as applying moisturizing emollients to keep the tissue supple and flexible. Ongoing physical therapy may also be necessary to maintain joint mobility and ensure the best possible functional outcome.