What Is Pus?

Pus, also known as purulent drainage, can be alarming when it is coming out of an incision or other types of wounds because it is a sign of infection, but the presence of pus is both good and bad news.

It is good news because this means your body has started to combat the infection by sending infection-fighting cells to the area that create pus. But it's bad news because your surgical incision or wound is clearly infected. 

In patients who have a compromised immune system, pus may never form in an infected incision, but most patients will find that infection leads to discharge from the area as well as the possibility of redness, pain or tenderness, swelling, and fever.

Identifying Pus

Drainage is not the same as purulent exudate, the medical term for pus. In fact, a wide variety of types of drainage are often normal, and are not pus, but are misidentified as pus. Actual pus is drainage that is full of dead white blood cells that rush to the site to help the body fight the infection. It also contains dead tissue and bacteria or fungi. 

Pus is typically white/yellow color but can be brown or even green. Some types of pus have a foul odor.

Not all pus is cause for alarm. A pimple, for example, is a normal part of life and is no cause for a trip to the emergency room, but is an example of pus forming at the site of an infection.

When to Call the Doctor

A surgical incision with pus should not be ignored, but many types of drainage are normal. Clear fluid or blood-tinged fluid that is largely clear, is considered normal unless there is a large quantity coming from the wound.

If you have identified drainage from a wound that is likely infectious drainage rather than normal drainage, it should be examined by a healthcare provider. At the very minimum, a call should be made to the physician who performed the procedure to provide an update about the state of healing. 

If there is no response from that individual, there are two choices—seek medical treatment during regular business hours or seek medical treatment at the emergency room.

That doesn't mean that a tiny speck of white drainage should lead to calling 911 at 2 a.m., but pus should not be ignored for days. Ignoring an infection can lead to serious problems, a longer recovery, and more scarring.

Calling your surgeon/physician should be a priority. Your surgeon may prescribe antibiotics, ointments or a special incision care program, or may not be concerned.

Antibiotics are important because they will help your body heal faster and may prevent the infection from becoming worse. In addition, your surgeon may want to see your incision in order to make sure there isn’t a deeper underlying problem.

Cleaning a Wound or Incision

You need to resist the urge to scrub your incision, slather it with antibiotic ointment, or clean it with alcohol or peroxide. Until your surgeon gives you new instructions, keep your incision clean by using soap and water like you normally would during a shower.

Do not scrub the area—gently wash it as you would a baby's bottom. No aggressive scrubbing is necessary and it can cause harm because an irritated wound becomes infected more easily and will also be more tender or even painful.

Keep the incision dry, and protect it with a clean bandage. You can leave it uncovered, but if drainage may be leaking from the site it can stain clothing and make a bigger mess than necessary. In general, do what was recommended in your instructions for incision care after surgery unless you are told otherwise.

Lab Tests

Your wound drainage may be collected and sent to the lab to determine what type of bacteria is causing the infection. This process is called a culture and sensitivity and the information from the test is used to determine what antibiotic the bacteria is sensitive to, in other words, the test will determine which antibiotic will kill the bacteria most efficiently.

A Word From Verywell

One of the most important things an individual can do after surgery is to prevent an infection from forming in the incision as the wound heals. If it is too late to prevent an infection, good wound care is the next best thing to prevention. Alerting your surgeon is also important, as antibiotics may become a part of your wound care plan. 

Plan to take the time to clean the wound appropriately, check the wound regularly for signs of healing, and be sure to protect it when necessary.