Cuts in the skin are a common injury that can range from an annoying papercut to a life-threatening laceration. A common question about cuts is: “How deep does a cut need to be before stitches are required?” This is an important question since it is often considered when deciding whether someone should seek medical care; however, the depth of a cut is not the only factor that determines the need for stitches (also called sutures). Incorrectly assessing the need for stitches can lead to complications like disfigurement from scarring, serious infection, or amputation.
When is it an emergency?
If a cut causes serious bleeding, this is a medical emergency. Blood loss can be life-threatening if the wound is deep or large enough to sever major blood vessels. In fact, bleeding is the number one cause of preventable death after an injury. Any vigorous bleeding, like blood creating a spouting effect from a wound, warrants calling 911. Apply firm direct pressure to the bleed until help arrives. If you are helping someone with a serious bleed, protect yourself from bloodborne pathogens by wearing gloves.
Another reason to go to the emergency room for a cut is if the injury is bad enough to cause problems below skin level. For example, did a broken bone cause a cut in the skin? Is the cut related to a hard knock on the head?
When are stitches needed?
Not every cut needs stitches. When stitches are needed, it means that the edges of a wound must be brought together and closed to prevent infection and optimize healing. This can be done with skin adhesives (also called liquid stitches), medical staples, or sutures.
If your wound needs stitches, you will likely have to go to an emergency room or urgent care center within 6–8 hours of the injury. Any prolonged time with an open wound longer than that timeframe increases the risk of infection. However, if longer than 24 hours have passed since the injury, it is unlikely that sutures will be placed by a healthcare provider and may in fact complicate the wound healing process that has already started.
Below are a few ways to understand if you may require stitches:
- Wash up. Start by cleaning the wound well with water. Washing the wound will allow you to assess the depth of your cut. Rinsing with cool or room temperature running water is best, but be sure that the water is clean to avoid contaminating the wound.
- Stop the bleed. In cases where there is no serious bleeding, but the blood has more of a slow oozing quality from the wound, you generally have time to apply pressure over the cut until it stops. In addition to serious bleeds, cuts that do not stop bleeding after 15 minutes of direct pressure using gauze or a clean cloth may require sutures. Secondary to washing out the wound, this step will allow viewing the depth and severity of the cut.
- Deep trouble. If the edges of the cut cause a gash or opening, you may require sutures. A deep cut is characterized as 0.25 inches, or 6.5 mm, in-depth (about the length of typical sunflower seed). Sometimes a deep wound is obvious because you can see deep structures like fat, muscle, or tendons inside the cut. If there is any loss of feeling or movement around a deep wound, this signals a definite need for medical treatment. A wound that is both long (greater than 0.75 in, or 20 mm) and deep is more likely to require sutures. On the other hand, short, deep puncture wounds are unlikely to receive sutures because of their ability to trap bacteria far beneath the skin.
- Face danger. Any cuts about the face have a potential for deformity or scarring that may be minimized if treated in a timely manner. Additionally, the face and neck are filled with delicate superficial nerves, glands, and vessels that require special attention if injured. If a cut occurs in the wrong part of the face, for example, it may disable someone from smiling or facially expressing other emotions as they did before.
- Busted joints. The skin is less likely to stay aligned for healing if the cut is over a joint. Getting sutures for a cut over a joint will allow the injured joint to move during healing without threatening to re-open the healing wound. This is especially true for cuts involving the hands and fingers. Infection is another concern for cuts that go deep enough to puncture the joint capsule. These types of infections can affect one’s ability to move the joint normally far into the future, as well as threaten a more serious infection than one involving only the soft tissues and skin.
- Fragility risk. Some conditions make the skin less likely to heal properly. Certain individuals, like the elderly, or those on medications like corticosteroids, have more thin or fragile skin and will require professional medical attention for cuts that would seem insignificant in others. Other chronic diseases like diabetes or peripheral vascular disease can also delay healing. In addition to closing the wound, an urgent care or emergency provider may recommend a frequent schedule of medical monitoring to follow the wound healing process and take any interventions that may be needed to keep the cut from separating or becoming infected.
What are other wound considerations?
Another point in deciding whether to get your wound evaluated by a medical professional may be less obvious: when was your last tetanus shot? Tetanus, or “lockjaw,” is a bacterial disease that can cause nerve and muscle dysfunction leading to death. The bacteria that causes tetanus infects the body by entering an open wound or other vulnerable places in the skin, like a severe burn. If you are uncertain or if you know your last tetanus vaccine to be longer than five years ago, then it is worth going to a clinic for evaluation and a possible booster tetanus shot.
Along these lines, consider the cleanliness of the cause of the cut. Was the cause of the wound considered contaminated or dirty? For example, animal bites or cuts created by human teeth have a much higher risk of infection, so antibiotics are frequently needed. The urgent care or the emergency room clinician will determine the type and number of days of antibiotics to adequately prevent the bacteria most likely to cause infection from multiplying. They will also determine whether to close the wound with stitches.
Lastly, could there be anything inside the wound? Anything penetrating the skin that becomes trapped is a potential nidus for infection or delayed wound healing. You may need x-rays in addition to a trained medical professional to explore the cut for any foreign bodies if there is a chance that something got lodged in the wound.
What not to do with wounds
Unless you will not reach medical care in the immediate future (such as if your injury occurs while performing remote work far away from the nearest clinic), do not use any antiseptic until a medical provider examines the wound. Some antiseptics can interfere with wound interventions like skin adhesives. Stick with clean water only to rinse out the cut that may need sutures.
Do not use non-medical adhesives like table glue or super glue as a substitute. This will not only prove an obstacle in re-cleaning the wound once you go for medical treatment, but it may also cause infection or keep the tissue from properly healing.
You should take off any jewelry involving the injured area. Swelling can occur shortly after a bad cut, which could create a tourniquet effect on that limb or digit. Jewelry like bracelets and rings may cut off the circulation, worsening the injury.
Alexander Trott, “Wounds and Lacerations: Emergency Care and Closure,” 4th ed., Elsevier, Philadelphia, 2012
American College of Surgeons, “Wound Home Skills Kit: Lacerations & Abrasions,” https://www.facs.org/~/media/files/education/patient%20ed/wound_lacerations.ashx
Kristen Ng, “Traumatic Arthrotomy,” Core EM, August 29, 2018, https://coreem.net/core/traumatic-arthrotomy/
Lacerations, Wounds, Trigger Fingers, and Burns,” Journal of the American Board of Family Medicine, September 28, 2020, https://www.jabfm.org/content/jabfp/33/5/799.full.pdf
Ronald Akiki and Raman Mehrzad, “Practical Management of Common Skin Injuries,
Uniformed Services University, “Stop the Bleed,” https://stopthebleed.usuhs.edu/
University of Michigan, “Cuts: When Stitches Are Needed,” https://www.uofmhealth.org/health-library/sid42906