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If you’ve had surgery, it’s normal to have some pain, redness, and swelling afterward. But it’s also important to watch for the signs of a postoperative infection.

Infections occur after 0.5% to 3% of surgeries, according to a 2023 review in JAMA. While many postsurgical infections are mild, some can have life-threatening complications.

In this article, find out more about how to tell if a surgical incision is infected. Understand the differences between normal postoperative pain and an infection. Learn when to call your doctor about wound changes and other signs of infection.

What Is a Surgical Site Infection?

A surgical site infection (SSI) is an infection of a surgical wound that occurs within 30 days of surgery. If the procedure involved an implant, a surgical site infection can occur within a year of surgery.

There are three major types of surgical site infections:

• Superficial incisional SSIs — Limited to the skin around the incision. They are the most common type of SSI.
• Deep incisional SSIs — Affect the layers beneath the skin, such as the muscles.
• Organ/space SSIs — Deeper infections, below the level of the incision. They may be as deep as the organs involved in the surgery and the areas around them. They’re the rarest type of SSI, but also the most serious.

SSIs occur when bacteria or other pathogens enter the surgical wound. This can happen before, during, or after surgery.

What Are the Signs of a Surgical Site Infection?

Like any wound, surgical incisions go through the stages of healing.

It’s normal to feel pain, redness, or swelling around your incision at first. Those are common during early wound healing stages. But if you notice things are getting worse, that’s a cause for concern.

Common surgical site infection symptoms include:

• Fever/chills — A fever of 100.5 F or higher after surgery is a sign of infection.
• Increasing pain — Pain around your incision should begin to decrease in the days after surgery. But if you notice your pain starting to get worse, it’s a potential sign of infection.
• Redness, swelling, or warmth that spreads — It’s common to have some redness, swelling, or warmth around your incision. But those should go away within a few days after surgery. If the redness, swelling, and heat get worse or spread, it’s a warning sign of infection.
• Purulent drainage (pus) — Clear, bloody, or pink discharge from your wound is normal after surgery. But thick, cloudy drainage that’s yellow, green, brown, or white is a cause for concern. It may also have a foul smell.
• Wound reopening — Also known as wound dehiscence, this can happen for several reasons. It may be a warning sign of infection.

It’s often easier to see the symptoms of superficial incisional SSIs because you can see changes to your wound. It can be harder to see the signs of deep internal infection after surgery, like deep incisional SSIs and organ/space SSIs. The biggest warning signs to look for are fever, chills, and pus drainage.

When should I call a doctor about the signs of a post-op infection?

Surgical site infections can have serious, potentially life-threatening complications. You should call your doctor immediately if you notice any of the above symptoms.

The American College of Surgeons (ACS) says you should also call your doctor if you notice these symptoms:

• Confusion.
• Diarrhea.
• Dizziness or a faint feeling when you stand.
• A fever of 102 F or higher.
• Headache.
• Rash.
• Vomiting.
• Worsening sore throat.

These could be warning signs that the infection has spread.

How Are Surgical Site Infections Treated?

Antibiotic medications are the most common treatment for surgical site infections. Your doctor may take a sample of the pus drainage. They do this to determine which bacterium is causing your infection and which antibiotic to prescribe.

Other potential treatments for SSIs include:

• Hyperbaric oxygen therapy (HBOT).
• Pain management and supportive care.
• Vacuum-assisted closure.
• Wound debridement.

What Are the Complications of Surgical Site Infections?

Without a quick diagnosis and proper treatment, SSIs can have serious, life-threatening complications.

People with SSIs typically have longer hospital stays and longer recoveries. They face a higher risk of intensive care unit (ICU) admission and hospital readmission. SSIs also raise the risk of death and disability, and can cause pain and mental strain.

SSIs may also lead to serious medical conditions. The most serious medical complication of an SSI is sepsis. Sepsis occurs when your body’s immune system goes overboard in response to an infection. Sepsis can lead to a serious condition called septic shock, organ damage, and even death.

Other complications of SSIs include:

• Abscesses (pus formations).
• Cellulitis.
• Complications from antibiotics.
• Increased scar tissue.
• Osteomyelitis (bone infections).
• Soft tissue infections.

What Are the Risk Factors for Surgical Site Infections?

Many different factors can increase your risk of SSIs. They can range from personal risk factors to things out of your control.

You may be at greater risk of SSIs if you:

• Are malnourished.
• Are obese.
• Are over 65 years of age.
• Are a smoker.
• Have a compromised immune system.
• Have an alcohol use disorder (formerly called alcohol addiction or alcoholism).
• Have diabetes.
• Have an existing infection.
• Have kidney disease.
• Have poor skin hygiene.
• Take steroids, such as prednisone.

External factors that can raise your risk of an SSI include:

• Contamination of surgical instruments, surgical workers, or the surgical environment.
• Dull surgical instruments.
• Emergency surgery or surgery involving the organs.
• Hypothermia (low body temperature) during surgery.
• Improper hair removal before surgery.
• Longer surgeries.
• Open surgical procedures.
• Poor ventilation in the operating room.
• A prolonged hospital stay before surgery.
• Use of implants or prosthetic parts.

How Can I Prevent a Surgical Site Infection?

Proper care before, during, and after your surgery can help lower your risk of developing an infection. Here are some of the steps you can take:

Discuss your health history

Before your surgery, talk about your health history with your surgical team. Mention any infections that you’ve had.

If you’re on any medications, let your surgical team know. Some medications, such as steroids, can increase your risk of postsurgical infections. You may need to adjust your usage before surgery.

Some medical conditions, like obesity and diabetes, can also increase your infection risk. Your surgical team may advise you to lose weight or make sure your diabetes is well-controlled.

Quit smoking

Smoking is a risk factor for post-op infections. Quitting smoking can help you lower your risk. It’s best to quit smoking before your surgery rather than waiting until later.

Don’t shave with a razor

Don’t shave your surgical site with a razor before your surgery. Using a razor can irritate your skin, which can increase the chance of bacteria growing — raising your risk of infection.

Your surgical team should use clippers for hair removal before surgery, if necessary.

Shower or bathe before the procedure

Take a shower or bath the night before or morning of your surgery. Ask your surgical team whether to use an antiseptic to kill bacteria on the skin.

Take an antibiotic

Your surgical team may give you a prophylactic antibiotic before your procedure. It can help prevent some of the more common bacterial infections.

Practice proper hand hygiene

Wash your hands frequently with soap and water or alcohol-based hand sanitizer before and after your surgery. When people visit you, ensure they do the same.

Take care of your wound

It’s important to practice proper incision care after your surgery.

Before you leave the hospital, your surgical team will give you instructions on caring for your incision. They’ll tell you how often to change your bandages and how to keep them clean and dry. They’ll also tell you when you can bathe and resume normal activities. If you have a surgical drain, they’ll tell you how to care for it.

Make sure to follow all the instructions you receive on caring for your incision. Be sure to clean your hands before and after changing your bandages. Your family and friends shouldn’t touch your incision or bandages unless they’ve received training.

If you have any questions about incision care, call your surgical team.

The UPMC Department of Surgery is one of the leading surgical departments in the United States. For more information on our services, visit our website.