Editor's note: This blog was originally published in October, 2016. It was updated and re-published in April of 2021.

A break in the skin through injury or surgery creates an open entry for bacteria to enter the body and begin to multiply. Recognizing the first signs of wound infection enables health care professionals to intervene with treatment swiftly. Here are some of the most common signs and symptoms associated with a wound infection:

1. Fever

After surgery, it is common for patients to run a low-grade fever of under 100 degrees Fahrenheit. However, if the fever goes to 101 or above and persists, that can indicate a possible wound infection. Patients who are running a fever may also have headaches and decreased appetite. Contaminated or infected wounds may benefit from antimicrobial dressings.

2. Feeling of Overall Malaise

Asking a patient how they feel can be an important part of assessing for wound infection. Individuals recovering from surgery or injury should feel better every day. When they do not and have continuing or worsening feelings of fatigue and lack of energy, this can be an indication that they have a localized or systemic infection. Sometimes patients recovering from surgery who develop an infection may feel better for a while and then suddenly feel much worse, thus making this simple question play a key role in your assessment.

3. Green, Tan, or Pungent Drainage

Normally, incisions or wounds drain clear or have slightly yellow exudate. Healthy wound drainage can be managed with dressings or negative pressure therapy. If the drainage becomes purulent with a pungent or foul odor it can indicate an infection.

4. Increased Pain in Wound

Generally, a patient who is healing well from surgery or an injury should find that their pain is subsiding. Although they may need pain medication at first, they should be able to reduce the use of medication and finally discontinue it comfortably over time. If a patient has continual or increasing pain, that can be a symptom of wound infection. Asking a patient about their pain level periodically and keeping track of their use of pain medication can help identify an underlying infection.

5. Redness Around the Wound

Initially, wounds appear slightly red because of the natural inflammatory process of healing, but that redness should gradually decrease in approximately 5-7 days. A deeper redness around the wound that continues to expand and worsen is a sign of wound infection. You can track whether redness is expanding by taking photos or drawing a line around the red area with a marker and checking to see whether the redness extends past the line.

6. Swelling of Wounded Area

Like redness, swelling is normal at the beginning stages of wound healing. However, swelling should be continually decreasing. Persistent swelling could be a further sign of infection or other complications.

7. Warmer Skin Surrounding Wound

Although it can be normal for skin surrounding a wound to feel somewhat warmer, when the skin around the incision feels very warm to the touch and doesn't start cooling down, that can indicate that the body is mounting a campaign against an infection. The heat is caused by the release of vasoactive chemicals increasing blood flow to that area. In addition, the immune system generates more heat by sending lymphocytes to produce antibodies to destroy the pathogen and phagocytes to ingest the dead bacteria.

8. Loss of Function and Movement

Another signal of wound infection that may require treatment is when the patient has lost the ability to move the wounded area normally. Although surgery and injuries can sometimes cause difficulty in movement that needs to be considered, most wounds don't injure underlying nerves, ligaments, tendons, bones, or joints. It can be common to have burning, numbness, or tingling around the wound when the patient tries to move, but they should be able to move the wounded area without a great deal of difficulty or pain.

The Importance of Recognizing Signs of Wound Infection

Whether a pathogen creates a wound infection is highly dependent on the strength of the individual’s immune system. Risks are increased when the wound is in a high-bacteria area of the body, the patient has a chronic condition such diabetes or vascular disease, or poor or inconsistent wound care is provided. Because surgical wound infection is one of the most common hospital-acquired conditions and has become a significant cause of morbidity and mortality, recognizing and treating wound infection need to be primary management objectives for health care professionals.