Ask the Doctors: No need to use rubbing alcohol on cuts

Dear Doctor: I was helping with Thanksgiving dinner when the paring knife slipped and sliced my finger. My aunt said to clean the cut with rubbing alcohol, which we didn’t have. I’ve always heard you’re supposed hold it under running water. How do you fix a cut?

Dear Reader: Your aunt isn’t alone in thinking that a cut should be cleaned with rubbing alcohol, but that’s not a good method. Rubbing alcohol is a clear liquid made up of approximately 70% denatured ethanol or isopropanol, and it is used topically in medical settings to clean injection or surgical sites. It’s highly effective due to its chemical properties, which break down the fat-based external membranes of bacteria, killing them. But in these cases, the alcohol is used on skin that is intact. When applied to an open wound, rubbing alcohol can cause tissue damage and actually slow the healing process. This also holds true for hydrogen peroxide, another common go-to disinfectant.

Instead, the best way to clean a cut is to apply a mild soap and hold it under a slow stream of cool or cold running water. Leave it there for at least five minutes. This gently cleanses the wound, and the cool water temperature causes the capillaries to constrict, which helps to slow bleeding. By doing this, you accomplish the first step of caring for a cut – or any type of wound – which is to stop the bleeding.

A cut may continue to bleed after you have finished cleaning it. If this happens, apply firm and steady pressure. Be sure that the cloth or gauze you use is completely clean, otherwise you risk reintroducing debris or potentially infectious materials into the wound. If the cut is deep enough and the blood soaks through the cloth or bandage, don’t remove it. You risk dislodging the clot that has begun to form. Instead, add a fresh and clean absorbent layer, and resume applying pressure to the cut.

When the bleeding stops, apply an antibiotic ointment. This helps to prevent infection and to keep the wound moist and lubricated. This last is important to optimal healing, and brings us to another myth about wound care. Despite what you may have heard, you don’t want to “air out” a wound. This encourages the formation of a scab or a crust, which can crack open and become infected. Instead, continue to use the antibiotic ointment, and keep the wound covered with a clean bandage. Once healing has progressed enough that the wound has closed and a scar has formed, continue to keep the area clean and intact.

While it’s safe to treat most minor cuts at home, get professional medical help for cuts with ragged rather than clean edges, when it’s deep enough that bone is visible, and when significant bleeding persists. Any type of puncture wound, which has a high risk of infection, should also be seen by a medical professional. Fever, red streaking, swelling, yellow or green pus, and excessive fluid are signs of infection and require immediate medical care.