What is healing by 2nd intention? A comprehensive guide to wound care

September 23, 2025 •

4 min read

Millions of surgical wounds, or those from trauma, cannot be closed with sutures and must heal naturally. What is healing by 2nd intention? It is the biological process where an open wound, often with tissue loss or contamination, is allowed to close and repair itself from the inside out.

Quick Summary

Healing by second intention is a natural wound closure process where the wound is left open to heal from the base upward through the formation of new tissue. This method is used for large, infected, or irregular wounds that cannot be sutured, relying on granulation, contraction, and epithelialization.

Key Points

Natural Closure: Healing by second intention is the body's natural process for closing open wounds from the base up when the edges cannot be approximated.
Granulation is Key: The process is defined by the formation of granulation tissue—new, pink, bumpy tissue—that fills the wound bed.
Wound Contraction: Myofibroblasts pull the wound edges inward, actively shrinking the wound's size during the proliferative phase.
Used for Complex Wounds: This method is necessary for wounds with significant tissue loss, contamination, or infection, such as deep pressure injuries or abscesses.
Longer Healing Time: Second intention healing is a slower process than primary intention, often taking weeks or months to complete.
Infection Risk: Meticulous wound care is essential to manage the higher risk of infection associated with leaving a wound open.

Understanding the Three Intentions of Wound Healing

Wound healing is a complex and fascinating biological process, but not all wounds heal in the same manner. Medical professionals classify wound closure into three primary categories or "intentions." While primary intention involves surgically closing a clean wound, and tertiary intention is delayed primary closure, the focus here is on what is healing by 2nd intention—a method for wounds that are too large, contaminated, or damaged to be closed immediately. This process relies on the body's intrinsic ability to regenerate and repair tissue over time.

The Step-by-Step Process of Second Intention Healing

Healing by second intention follows the body's natural four phases of wound repair, but with some distinct characteristics due to the open nature of the wound:

Hemostasis: The process begins immediately after the injury, with blood vessels constricting and platelets aggregating to form a clot. This creates a fibrin mesh, which acts as a scaffold for the healing process to follow.
Inflammation: A more pronounced and intense inflammatory response than in primary healing occurs. The body sends immune cells to the site to clean up debris, bacteria, and dead tissue. This phase is crucial for preparing the wound bed for new tissue growth.
Proliferation (Granulation and Contraction): This is the hallmark of second intention healing. The wound bed fills with new, healthy tissue called granulation tissue, which is rich in new blood vessels, fibroblasts, and collagen. Simultaneously, specialized cells called myofibroblasts at the wound edges begin to contract, actively pulling the edges of the wound inward to decrease its overall size. The new epithelial layer can only begin to cover the wound once it is filled with this granulation tissue.
Maturation (Remodeling): This final phase can last for months or even years. The scar tissue remodels, and collagen fibers reorganize, strengthening the repaired area. The resulting scar is typically larger and less cosmetically appealing than those from primary intention healing, but it effectively closes the wound.

Comparison: Primary vs. Secondary Intention

To fully appreciate the specifics of second intention healing, it helps to compare it with its primary counterpart. This table highlights the key differences.


Feature	Primary Intention Healing	Secondary Intention Healing
Wound Type	Clean, straight-edged wounds with minimal tissue loss.	Large, open, irregular wounds with significant tissue loss or infection.
Wound Closure	Closed immediately with sutures, staples, or adhesive.	Left open to heal naturally from the bottom up.
Tissue Required	Minimal formation of new tissue.	Significant formation of new granulation tissue.
Time to Heal	Generally faster healing time.	Significantly longer healing time, can be weeks or months.
Scarring	Fine, linear, and minimal scarring.	Larger, more extensive, and often visible scarring.
Infection Risk	Lower risk of infection.	Higher risk of infection due to exposure.

Types of Wounds That Require Second Intention Healing

Not all wounds are candidates for primary closure. Second intention healing is the necessary approach for several wound types, including:

Deep pressure injuries (bedsores): These wounds, which often expose bone or muscle, require healing from the deepest point outward.
Burns: Especially second- or third-degree burns with extensive tissue destruction where skin grafts may not be possible initially.
Abscesses: After an abscess is incised and drained, the cavity is left open to heal by second intention to prevent re-infection.
Traumatic injuries: Wounds with large amounts of tissue loss or those that are heavily contaminated, such as from blast trauma.
Dehisced surgical wounds: When a surgical incision breaks open after closure, it is often managed as a secondary intention wound.

Effective Management of Wounds Healing by Second Intention

Proper wound care is paramount for successful second intention healing, as these wounds are more vulnerable to complications like infection. The following are crucial aspects of management:

Regular Debridement: Removing dead or damaged tissue is essential for promoting the growth of new, healthy granulation tissue. This can be done through various methods, including surgical, enzymatic, or autolytic debridement.
Dressing Selection: The choice of dressing is vital for maintaining a moist wound environment, which promotes healing. Dressings such as alginates, hydrogels, and foam can help manage exudate and protect the wound bed. A systematic review published in the Cochrane Database of Systematic Reviews notes that while many dressings are available, evidence for one type being superior to another for accelerating healing is limited. The best choice often depends on the specific wound characteristics.
Infection Control: Due to the open nature of the wound, infection is a major risk. Careful monitoring for signs of infection (e.g., increased pain, redness, pus, fever) and prompt treatment with antibiotics, if necessary, are critical.
Optimal Nutrition: The body needs significant energy and nutrients to rebuild tissue. Ensuring adequate protein, vitamin C, and zinc intake supports the entire healing cascade, from collagen production to immune function.
Patient Education: Given the lengthy healing time, patient and caregiver education on proper wound care techniques, signs of complications, and expectations is essential for compliance and positive outcomes.

Conclusion

Healing by 2nd intention is a powerful testament to the body's regenerative capabilities. While more demanding and time-consuming than primary closure, it is the appropriate and often necessary pathway for complex, open wounds. By understanding the distinct stages of this process and diligently managing the wound with proper care, it is possible to achieve complete healing and successful wound closure, even in the face of significant tissue damage. This natural, bottom-up approach to repair underscores the resilience of the human body and the importance of meticulous wound management in supporting it.

Frequently Asked Questions

The main difference is the method of closure. In primary intention, the wound edges are surgically brought together (e.g., with sutures). In secondary intention, the wound is left open to heal naturally from the bottom up, requiring the body to form significant new tissue.

Wounds that typically heal by second intention include large, deep, or irregular wounds with extensive tissue loss, infected wounds, abscesses after drainage, and some severe burns or pressure injuries.

The healing time varies greatly depending on the wound's size, location, and the patient's overall health. It can range from several weeks to many months, as the body needs time to generate new tissue and contract the wound.

Granulation tissue is the new, vascularized connective tissue that forms on the surface of a healing wound. It is typically pink or red, bumpy, and fragile, and its purpose is to fill the tissue defect so that new skin can grow over it.

Yes, because the wound is open to the external environment for a longer period, there is a higher risk of infection. This is why careful and consistent wound care, including regular dressing changes and monitoring, is crucial.

Compared to primary intention, wounds healing by second intention typically result in a larger, more pronounced scar. The extent of the scarring depends on the wound's size, depth, and location, as well as individual factors.

Wound contraction is a vital part of second intention healing, where specialized cells pull the wound edges inward. This process significantly reduces the size of the wound and accelerates healing, though it may cause distortion in areas like joints or facial features.

The wound itself and the surrounding area can be sensitive and cause discomfort, especially during dressing changes. However, second intention healing is often associated with less post-operative pain than some other reconstructive methods.