The body is equipped to repair damaged tissue, a process known as wound healing. When a cut occurs, medical intervention (such as stitches, staples, or surgical glue) aims to bring the separated tissue edges together. This alignment allows the body to heal efficiently, known as healing by primary intention. Leaving a significant cut unclosed forces a more complex repair process, which can lead to complications and a different outcome.
When a Cut Needs Professional Closure
Determining whether a cut requires professional closure involves assessing several characteristics. A cut needs medical attention if the skin edges gape open, preventing them from staying together. This gaping often occurs in wounds deep enough to expose underlying structures such as fatty tissue, muscle, or bone.
Physical dimensions are a guideline; cuts often require stitches if they are longer than about three-quarters of an inch or deeper than a quarter of an inch. Location is also important, as wounds over joints or areas of high movement, like hands and feet, require closure to prevent constant reopening. Cuts on the face or other cosmetically sensitive areas are frequently closed to minimize scarring, even if they are not particularly deep.
A continuous flow of blood that does not stop after 10 to 15 minutes of firm pressure signals immediate care. The window for effective closure is limited, generally within six to eight hours of the injury for most body areas. Wounds that are heavily contaminated, such as puncture wounds or those from crush injuries, may need to be cleaned and left open temporarily before a delayed closure to reduce infection risk.
How Unstitched Wounds Heal
When a deep wound is left unstitched, the body must heal through a process called secondary intention. The separated wound edges cannot be drawn together, so the open space must be filled in from the base upward. This requires an extended and intense healing response.
The initial step involves the formation of granulation tissue, a temporary matrix of new connective tissue and capillaries. This tissue acts as a scaffold to fill the defect, bringing a fresh blood supply to the area. Granulation tissue must grow until it reaches the level of the surrounding skin before the top layer, the epithelium, can fully cover the surface.
Wound contraction is a feature of secondary intention healing, mediated by specialized cells called myofibroblasts. These cells pull the wound edges inward to decrease the open area. While this mechanism reduces the wound size, it results in a much longer healing time compared to a stitched wound, which is already approximated.
Risks of Skipping Stitches
Failing to close a wound that requires approximation introduces two major consequences: infection and significant scarring. An open wound presents a direct entry point for bacteria, creating an ideal environment for microbes to multiply. This increases the risk of localized infection, characterized by redness, swelling, warmth, and pus.
If the localized infection is not managed, it can spread deeper, leading to cellulitis or, rarely, a systemic infection. The second and more common outcome is the formation of a wide, noticeable scar.
Secondary intention healing requires generating a large volume of granulation tissue to fill the defect. This extensive tissue generation and contraction lead to a wider, less refined scar compared to the thin line left by a stitched closure. Excessive formation of connective tissue can result in raised, thickened scars, such as hypertrophic or keloid scars, which may cause functional or cosmetic concerns.