How to Tell If a Cut Is Infected

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An infected cut can lead to a serious illness if left untreated. In many cases, skin infections like staph, strep, or methicillin-resistant Staphylococcus aureus (MRSA) get started from the tiniest of cuts. Even a little cut that doesn't need stitches can cause big problems if it gets infected and goes untreated. So, how can you tell if a cut is infected?

Close up hand of doctor wrapping a bandage to the knee of patients
wera Rodsawang / Getty Images

Signs of Infection

To tell if a cut is infected, look for these signs:

  • Swelling
  • Redness
  • Local fever (the cut feels hot compared to areas around it)
  • Draining pus (the cut is oozing thick, gooey stuff)

If a cut or scrape becomes infected, you need to see a healthcare provider.

In most cases, only doctors, physician assistants, or nurse practitioners can give you antibiotics to fight the infection. Untreated, infected wounds can become serious. The worst-case scenario is that an infected cut develops into a full-body (systemic) infection.

To tell if you are developing a bigger infection, look for:

  • Fever over 100 degrees Fahrenheit (taken orally or rectally): It's one thing if the cut is hot, but when the whole body has a fever it means the infection is spreading.
  • Body aches: Especially in joints and areas not adjacent to the injury, these are a sign of a widespread infection. It's understandable if your cut is sore, but the rest of you shouldn't be.
  • Nausea or diarrhea: These are both indicators that an infection has moved from the local injury to affect other body systems (specifically, the gastrointestinal system).

When to See a Doctor

If you have an infected cut or are developing a systemic infection, see a doctor. Once a cut gets infected, you're going to need a doctor's help. Once an infection is identified, antibiotics will be necessary to eliminate it. There are many antibiotics available, and different antibiotics work on different bacteria.

To figure out which drug is right for your situation, the physician might need to swab your injury and send the swab to be cultured. The material will be examined microscopically and will be placed in culture media to see if any concerning bacteria grow.

As soon as the bacteria grow enough, the exact types will be identified. If nothing concerning grows other than what is expected from healthy skin, the cut is not infected and no antibiotics will be needed. If concerning bacteria are found, they are tested to see which antibiotics are best at killing them and stopping the infection.

Treatment

If the physician, physician's assistant, or nurse practitioner does prescribe antibiotics, take them all. Often, you'll start to feel better within a day or two of beginning your antibiotic regimen and you might be tempted to stop taking them. Don't do it.

Even though you feel better, the antibiotics haven't killed all the bacteria yet. If you stop, the bacteria that had successfully survived the first few days of antibiotics will reproduce. These are the stronger bacteria, and their offspring will be much more resistant to that antibiotic.

Prevention: Keep It Clean

To avoid an infected cut, it's important to keep cuts clean as they heal. Most of the time, soap and water are all you need. Whether you use an antibiotic ointment or not is up to you, but it's really not necessary.

It helps to cover a cut with an adhesive bandage, but remember to change the bandage every day and wash the cut with soap and water.

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Article Sources
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  1. TeensHealth. Cuts, Scratches, and Scrapes. Updated January 2015.

  2. Centers for Disease Control and Prevention. What is sepsis? Updated August 27, 2019.