What is Suture Hypersensitivity?
In the field of immunology, hypersensitivity is a common issue. This is when the body’s immune system overreacts, causing an extreme and sometimes harmful response to an antigen, which is a substance that prompts the immune system into action. Sometimes, hypersensitivity is related to inherited genes, specifically those associated with human leukocyte antigens (HLAs), which play a significant role in the immune response.
Suture hypersensitivity is a group of conditions caused by an extreme immune response to suture material, which serves as an external antigen. Even though it’s often considered as a skin condition, hypersensitivity can also develop in deeper tissues, and has a significant impact on wound healing. Distinguishing between post-surgical infections and hypersensitivity reactions is critical.
If a surgical wound is causing issues, specialists like allergists and dermatologists may need to get involved. They can help figure out what’s going wrong and how to manage it. If suture hypersensitivity is the issue, it could lead to longer hospital stays and higher healthcare costs. Therefore, a team of professionals, including dermatologists, allergists, and specialized nurses, is important for early detection, diagnosis, and treatment to reduce such complications. If a hypersensitivity reaction is identified, the recommended treatment is a swift recognition of physical signs, additional allergy testing, fresh suture materials, and starting topical steroids as quickly as possible to prevent further complications.
Currently, there are no established screening methods for identifying allergens related to surgery. However, some studies have proposed testing for specific allergens in patients who are suspected of having suture hypersensitivity. This could reveal relevant allergens and help avoid future issues related to exposure.
What Causes Suture Hypersensitivity?
When doctors use stitches to close a wound, they’re inserting a foreign object into your body, which triggers an immune response. The way your body responds depends on the type of stitch material used, the tissue being stitched, and your immune system. This reaction is usually more intense if the stitches are absorbable (they dissolve on their own over time), synthetic, large, or made from numerous threads.
The immune response can be caused by the body’s innate (inborn, always present) immune system, the adaptive (changes and adapts over time) immune system, or a combination of both. Macrophages, a type of white blood cell, are usually the major players in this reaction, causing what’s known as a type IV hypersensitivity reaction.
Normally, when a foreign object like a stitch is in the body, the immune system recognizes it as something that isn’t supposed to be there. The stitches then trigger a macrophage-dominated reaction that lasts for weeks. Macrophages may change their shape into epithelium-like cells, which then group together to form granulomas, resulting in a specific type of inflammation. This reaction can occur even without an adaptive immune response.
Absorbable stitches rely on the body’s reaction to dissolve in a timely manner. The hypersensitivity reactions usually occur towards the end of the stitch absorption process. The thickness of the stitches might be the key factor in this process.
The body’s response can be divided into two phases – acute (immediate) and chronic (ongoing), with both types of reactions typically seen within two days following surgery. Differences in the body’s reaction after the acute phase start to become more visible once the absorption process of the stitches begins. Once absorbed, the site is marked by a collection of monocytes (another type of white blood cell).
Non-absorbable stitches, on the other hand, remain in the body indefinitely and cause a different tissue reaction. They initially cause mild swelling and a gathering of a certain type of white blood cell around the site, followed by an increase in another type of white blood cell, and a decrease in the initial type. Eventually, fibroblasts (cells that produce collagen and other fibers) create a fibrous capsule around the stitch.
The reaction to silk, a common type of non-absorbable stitch, is usually characterized by the stitch encapsulated by a thick layer of fibrous tissue. This is often surrounded by cell layers which vary in thickness. In more cellular reactions, blood vessels may be prominent. Occasionally, the response appears much like granuloma, which is a reaction to materials that are too large to be ingested by macrophages.
The extent of the tissue reaction also depends on the type of tissue that’s being stitched. For example, stitches placed within the bladder can cause significant tissue reactions and form stones, whereas the reaction isn’t as significant with certain types of stitches.
The formation of granulomas might be associated with a specific immune reaction of macrophages. A giant cell reaction to foreign material is thought to underlie various clinical signs and symptoms of stitch hypersensitivity.
Risk Factors and Frequency for Suture Hypersensitivity
People rarely have reactions to suture material, but the immune status of the patient could affect these reactions. Those who have allergies or autoimmune diseases are at a higher risk of having hypersensitivity reactions, while individuals with suppressed immune systems may be less likely to have such reactions. A study found minimal response to several types of sutures in patients who underwent renal transplants. Sutures might disturb surrounding healthy tissues without any cellular response.
Chronic irritant dermatitis, allergic contact dermatitis, and contact urticaria are potential reactions to sutures. The most common materials causing such reactions are silk, catgut, and chromicized catgut. Fewer reactions are observed with synthetic absorbable sutures, such as polyglactin 910 and poliglecaprone 25. Non-absorbable stitches, like polyamide 6/6 and nylon, have a low risk of allergic reaction. Other suture materials like polypropylene, and ones sterilized with ethylene oxide and triclosan, have reported hypersensitivity reactions. Even the dye used to color sutures can cause hypersensitivity reactions.
Acrylic resin, cyanoacrylate, and 2-octyl cyanoacrylate found in adhesives, plastics, paints, inks, and skin adhesives can also cause hypersensitivity reactions. In the surgical context, these materials are often found in surgical strips used for wound closure. Acrylates exposure may come from sources such as sculptured nails and bone and dental cement, increasing the risk of reactions. Other allergens in adhesives include colophony, abitol, abietic acid, benzoyl peroxide, rubber accelerators, and antioxidants. Even hydrocolloid dressings, which contain colophonium, could cause hypersensitivity reactions.
Compared to catgut, silk is cheaper and easier to sterilize. Silk also reacts less with body tissues and can provide stronger wound closures. Allergic reactions to silk sutures are rare, but in some cases, removing the sutures has eliminated the allergy, which has been linked to conditions like asthma, interstitial cystitis, and necrotizing granulomas.
Clinicians often prefer Vicryl sutures because they have low antigenicity and rarely cause inflammation. Allergic reactions to Vicryl sutures are very rare, but have been reported as itching, swelling, pain, and fluid-filled swelling. As of now, there is no standardized testing method for these reactions, but testing a single suture on the skin can help identify a potential suture hypersensitivity.
Signs and Symptoms of Suture Hypersensitivity
Before any surgery, it’s important to find out if the patient has allergies or any reactions to suture materials used in previous procedures. Also, pay attention to whether their current symptoms are close to areas where they had surgery before. There are several signs we look for to see if there’s a problem with the sutures, like:
- Redness
- Swelling
- A lumpy mass
- The suture coming out through an incision
- Itchiness
- Fluid buildup
- Pain
- Pocket of clear fluid under the skin (seroma)
Additional potential issues could include surgical scar tissue, the wound reopening, infection, intestine blockage along the line of the suture material, and a type of inflammation called granuloma. If a patient comes in with an infection or fluid leaking from the wound, we should consider the possibility that they’re having a reaction to the suture.
Testing for Suture Hypersensitivity
When your doctor suspects your body might be reacting too strongly to stitches used in a surgery or procedure, it can be tough to tell if it’s just part of the normal healing process or if it’s a genuine sensitivity or allergy to the stitches. However, the only time this difference really matters is when the reaction is quite severe.
Most of the time, extra tests aren’t necessary unless there’s a specific need for them. If your doctor wants to be certain, they could do a skin allergen test. This test involves placing a stitch of the same material under your skin again and then observing whether your body reacts to it. For people who’ve had cancer in the past, a biopsy might be needed just to make sure the cancer hasn’t returned.
Certain skin tests, like the American Contact Dermatitis Society Core allergen series, the North American Contact Dermatitis Group patch test, and the thin-layer, rapid-use (TRUE) test are key to finding out what’s causing an allergic reaction. However, keep in mind that none of these tests can detect an allergy to a component called 2-octyl cyanoacrylate found in some skin glues. When these patch tests aren’t available, an alternative option might be to place a stitch under the skin or to just place the offending substance against the skin. In cases where a skin glue is suspected to be causing an allergy, a separate skin test is recommended.
Lastly, if your doctor thinks the issue might be deeper under the skin, they may use an ultrasound to help diagnose. Suture granulomas, a type of tissue inflammation caused by stitches, would show up on an abdominal ultrasound as small, rounded, low-echo areas. A double line of high echo might even be seen, which is a sure sign of a suture granuloma on an ultrasound. If it’s visible on the skin, the granuloma might show signs of peripheral vascularization, which is the formation of small, new blood vessels around the area.
Treatment Options for Suture Hypersensitivity
The kind of reaction that body tissues have to different types of suture material – the thread used to sew up a wound – is an important factor when deciding which type to use. Typically, non-absorbable sutures, or sutures that don’t dissolve on their own, cause the least reaction. Synthetic absorbable sutures, which do dissolve eventually, cause a moderate reaction. Sutures made from materials that come from other species cause the most reaction.
If a person has a hypersensitivity reaction – basically, an allergic reaction – to a suture, several factors influence treatment. These include how much the reaction is interfering with healing, if there are other complications, and how long it’s been since the original procedure. The best way to address an ongoing inflammation or irritation is typically to surgically remove whatever is causing the irritation. In addition to this, the healthcare team might use several other treatments. This could include creams containing corticosteroids, which reduce inflammation and itching, oral antihistamines to reduce allergic reactions, topical immune response modifiers to help control inflammation and itching, and moisturizers to soothe the skin. In some cases, corticosteroids might be given as a systemic treatment, meaning they work throughout the body, rather than just on the skin.
What else can Suture Hypersensitivity be?
It’s important for doctors to make sure that after a surgery, complications like scarring, bleeding, internal bleeding (hematoma), infections, abscesses (localized collections of pus), and wound splitting (dehiscence) are not being mistaken for an allergic reaction. In some instances, these complications can actually be a result of an allergic reaction (hypersensitivity).
An allergic reaction to surgical stitches (suture hypersensitivity) can look a lot like disorders characterized by inflammation and lumps (primary granulomatous disorders). Therefore, it’s crucial not to mistake this allergic reaction for a serious disease like cancer (malignancy) or a returning infection in the wound. To tell the difference, a small sample can be taken from the wound using a thin needle (fine-needle aspiration) and then tested for bacteria (wound culture with staining).
What to expect with Suture Hypersensitivity
The outlook for a patient dealing with suture hypersensitivity complications largely depends on the tissues involved and how severe these complications are. In many cases, this condition resolves itself over time without leading to serious outcomes.
Possible Complications When Diagnosed with Suture Hypersensitivity
Problems caused by allergic reactions to suture materials can vary depending on the kind of material used in stitching up wounds and the body part being treated. Generally, increased inflammation, blood flow, and foreign body response can make wound healing problematic. Several complications can occur, such as:
- Postoperative adhesions – when your tissues stick together
- Wound dehiscence – when a surgical cut reopens
- Infections
- Intestinal blockade along the suture line, especially if the patient previously developed sensitivity to the suture material
Suture materials can increase the chances of a low-level harmful bacteria growth at the surgery site. Could result in types of infections like Staphylococcus epidermidis. These reactions can lead to stone formation in the urinary system, which can create more complications through obstruction and infection. For surgeries involving blood vessels and the digestive tract, allergic reactions to sutures might cause the surgical connections to fail.
Preventing Suture Hypersensitivity
Patients should let their doctor know about any allergies they’ve had in the past. If a patient has any reactions to something, it’s important to stay away from whatever caused it to avoid more problems. It’s also crucial to recognize early signs of a possible allergic reaction to surgical stitches. Some of these symptoms might include redness, swelling, a lumpy area, the stitch coming out through the cut, itching, fluid buildup, pain, fluid-filled pockets, and changes after surgery. If a patient notices any of these issues, they should reach out to their primary care team immediately to get the right treatment. Following the healthcare team’s advice regarding diet, follow-up appointments, and taking care of the wound is key to healing properly.
