Absorbable sutures, often called dissolvable stitches, are specialized medical threads engineered to provide temporary support to a healing wound before being naturally broken down and eliminated by the body. They are commonly used for internal surgeries and closing deep layers beneath the skin, eliminating the need for manual removal. These sutures, made from synthetic polymers (like polyglycolic acid) or natural materials (like treated gut), are designed to degrade over a predictable period. Degradation occurs through the body’s natural mechanisms, primarily hydrolysis (water molecules breaking down polymer chains) or enzymatic degradation.
Expected Absorption Timelines and Variables
The timeline for complete absorption is highly variable, depending on material type and individual biological factors. Absorption can range significantly, from a few weeks to several months. For instance, fast-absorbing sutures used for temporary skin support dissolve quickly, while materials intended for deep tissue support, such as Polydioxanone (PDS), can maintain integrity for months.
The material type is the primary determinant of this timeline. Synthetic polymers are broken down by hydrolysis, while natural materials like chromic gut are degraded by the body’s enzymes. Suture size also plays a role, as a thicker strand contains more material and takes longer to break down than a finer one.
The suture’s location also influences the rate of dissolution. Areas with a rich blood supply, such as the mouth or highly vascular internal organs, tend to accelerate the absorption process. Conversely, tissues with lower metabolic activity or restricted blood flow, such as fat, cartilage, or an extremity, will slow the rate of breakdown.
Why Stitches Fail to Dissolve on Schedule
When an absorbable suture remains visible or palpable past its anticipated lifespan, it is usually due to mechanical and biological factors impeding degradation. A common cause is a minimal inflammatory response, which is necessary for the body to break down the material. If the tissue reaction is too mild, the degradation process can slow significantly, though this mild reaction is often desirable for minimizing scarring.
The size and bulk of the knot itself is a mechanical factor contributing to delayed dissolution. The tight, dense structure of a surgical knot contains a high concentration of material, making it resistant to rapid penetration by water and enzymes. These knots naturally take longer to fully dissolve compared to the thinner running suture line.
The body may also push the foreign material out in a phenomenon known as “suture extrusion” or “spitting.” This occurs when the immune system treats the suture as a foreign object, forcing the material toward the skin surface instead of dissolving it. This can happen weeks or months after the wound has healed, often resulting in a small, raised, reddish bump.
In rare instances, the issue is misidentification of the suture material. Non-absorbable materials, such as nylon, silk, or polypropylene, are designed to remain permanently unless manually removed. If a patient assumes a non-absorbable suture was meant to dissolve, it will persist indefinitely.
Managing Persistent Sutures at Home
If a persistent absorbable suture is not causing pain or infection, patience is the best approach. Routine wound care supports the body’s natural processes. This includes carefully cleaning the area with mild soap and water, then gently drying it.
For an exposed knot or thread irritating the skin, applying a warm, moist compress for a few minutes can encourage the material to soften or migrate slightly. This gentle warmth increases local circulation, which may help accelerate the final stages of degradation.
If a small, superficial knot is clearly protruding and causing irritation, some practitioners advise safely trimming the exposed thread. This involves cutting the thread flush with the skin using sterilized scissors, ensuring no tension is placed on the underlying suture. Trimming the exposed portion removes the source of local irritation, allowing the embedded portion to continue dissolving.
Any attempt to trim or remove a visible stitch must be done only after consulting the surgeon or healthcare provider. Never attempt to pull a stitch that is not freely mobile, as this can disrupt healing tissue and potentially lead to wound separation or infection. The goal of at-home management is to maintain cleanliness and comfort while awaiting dissolution.
Warning Signs and When Urgent Medical Review is Necessary
While a slowly dissolving suture is generally benign, certain signs indicate a complication requiring prompt medical attention. These urgent warning signs include:
- Increasing redness around the stitch that spreads beyond the wound edges (cellulitis), indicating the body is struggling to contain bacteria.
- The presence of pus or a foul-smelling discharge from the wound site, suggesting an active infection.
- Persistent or worsening pain not relieved by over-the-counter medication.
- Excessive swelling or a feeling of warmth at the site.
- A fever or chills, indicating a systemic reaction requiring immediate medical review.
Sometimes, the persistent suture causes a foreign body reaction, leading to chronic irritation and a granuloma (a small, hard bump). If a suture continues to cause significant discomfort long after the expected healing time, a medical professional can easily clip and remove the remaining material. This simple, sterile office procedure prevents further inflammation and allows healing to proceed.