Table of ContentsView AllTable of ContentsWhat Is Pus?What Does It Do?PreventionTreatmentWhen to See a Provider
Table of ContentsView All
View All
Table of Contents
What Is Pus?
What Does It Do?
Prevention
Treatment
When to See a Provider
Pus is a thick yellowish, whitish, or greenish fluid made up of dead white blood cells, dead tissues, and dead bacteria or fungi. Also calledliquor purisor purulent exudate, it is produced as part of the body’s response to an infection. Pus is usually odorless but can emit a foul odor if an infection is severe.
Pus can occur with common skin conditions likeacneor when a break in the skin allows germs to enter underlying tissues (such as might occur with a cut orsurgical incision). Surgeries or diseases like appendicitis or diverticulitis can also cause infections in deeper tissues that lead to pus.
Photo: Angela Palmer
How Does Pus Form?
When an infection occurs, theimmune systemwill send different white blood cells (leukocytes) to fight it. These includemacrophagesand dendritic cells that surround and absorb the invader, killing them through a process known asphagocytosis-induced apoptosis. This is when white blood cells “commit suicide” to kill the invader they have absorbed.
In the aftermath, dead white blood cells, dead bacteria or fungi, and dead tissues will start to accumulate, resulting in pus.
Pus is usually an opaque, white-yellow color. It can also be brown or green. Different colors of pus can hint at different infections, but a formal diagnosis from a healthcare provider is necessary to confirm the cause.
Pimple vs. AbscessA collection of pus within or just beneath the outermost layer of skin (epidermis) is called apustuleor pimple. The accumulation of pus within an enclosed space in deeper tissues is known as anabscess.
Pimple vs. Abscess
A collection of pus within or just beneath the outermost layer of skin (epidermis) is called apustuleor pimple. The accumulation of pus within an enclosed space in deeper tissues is known as anabscess.
What Does Pus Do?
With pustules, your body may be able to slowly absorb and break down the pus without treatment. The pustule may also drain naturally, eventually shrinking and drying up.
Smaller abscesses near the surface of the skin may also do the same, but larger ones or those inside the body usually need to be drained.
Skin Infections
Many skin conditions can cause pus, some of which include:
Internal Infections
Pus-filled abscesses can form internally, such as in the mouth, internal organs, or deeper tissues. This can be a result of an injury, surgical complication, or bacterial or fungal infection that becomes systemic (affects the whole body).
There are many different causes of internal abscesses, examples of which include:
There are things you can do to reduce your risk of developing an infection with pus:
Before and After Surgery
Between 1% and 3% of people who have surgeries develop an SSI, according to the Centers for Disease Control and Prevention (CDC).
There are steps you can take before and after any procedure to reduce your risk of an SSI.
Before SurgeryThe night before surgery, wash your whole body with soap in the bath or shower.Do not shave near the surgical site. It can irritate the skin and increase your risk of infection. (If shaving is needed, the surgical staff will do it for you.)
The night before surgery, wash your whole body with soap in the bath or shower.
Do not shave near the surgical site. It can irritate the skin and increase your risk of infection. (If shaving is needed, the surgical staff will do it for you.)
Family or friends should wash their hands before visiting and should not touch your wound.
Always wash your hands before and after caring for the wound.
Inspect your incisiondaily for signs of infection.
Do not scrub your incision or use antibiotic ointment, alcohol, or peroxide unless your healthcare provider tells you to.
Clear or blood-tinged drainage from a surgical wound is considered normal unless there is a large amount of it. Wound drainage can last anywhere from one to five weeks, depending on the extensiveness of the procedure.
However, if you have cloudy, creamy, or foul-smelling drainage, call your healthcare provider immediately as this is a sign of an infection.
If an infection causes pus, it more often than not requires treatment. Depending on the severity of the infection, this might include:
Verywell / Laura Porter
Antibiotics
Bacterial infections are treated withantibiotics.
Your healthcare provider may collect a sample of pus and send it to a lab forcultureand sensitivity testing. This will help determine which type of bacteria you have and which antibiotic may be most effective at treating it.
Topical antibiotics can also be used for superficial fungal infections, mainly to prevent asecondary infection. This is when a fungal skin infection causes a break in the skin that allows bacteria to enter.
Fungal infections are directly treated withantifungals.
Drainage and Tissue Removal
In some cases, anabscess drainagemay be needed to clear pus. In such cases, if pus is not cleared, the infection may be harder to resolve. At the same time, the infection may spread into the bloodstream, causing a potentially life-threatening reaction known assepsis.
External abscesses may be lanced (cut) or drained with a needle and syringe.
A surgeon or interventional radiologist may drain an internal abscess. The catheter time duration depends on the size and cause of the abscess. The catheter may need to be left in for as little as a few days and as long as several weeks to months, depending on the problem
Surgical debridementmay be needed for large abscesses to remove dead tissues (as dead tissues are hotbeds for infection). It involves thoroughly cleaning the wound and removing anynecrotic(dead) or infected tissues along with any debris.
When to See a Healthcare Provider
Let your healthcare provider know if you experience a pus-like discharge from any part of your body. This is particularly important if you recently had surgery.
Seek urgent medical care if you have any of the following symptoms following surgery or the treatment of a wound:
Ignoring an infection can lead to more scarring and a longer recovery. It can also put you at risk of serious and even life-threatening complications, such as sepsis.
Summary
Your body produces pus as a response to infection. Pus is made up of dead white blood cells, bacteria or fungi, and tissue debris.
Proper wound care can prevent pus from developing. If an infection causes pus, treatment may include antibiotics, pus drainage, and possibly surgical debridement.
11 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Icahn School of Medicine at Mount Sinai.Surgical wound infection - treatment.Kobayashi SD, Malachowa N, Deleo FR.Pathogenesis of staphylococcus aureus abscesses.Am J Pathol.2015;185(6):1518-27. doi:10.1016/j.ajpath.2014.11.030University Health News.Pus: an unmistakable sign of infection.St. Elizabeth’s Medical Center.Abscess drainage.New York State Department of Health.Bacterial skin infections: Impetigo and MRSA.Centers for Disease Control and Prevention.Surgical site infections (SSIs).Bajracharya GR, Esa WAS, Mao G, et al.Regional analgesia and surgical site infections after colorectal surgery: a retrospective cohort analysis.Braz J Anesthesiol. 2022:S0104-0014(22)00074-4. doi:10.1016/j.bjane.2022.06.002Johns Hopkins Medicine.Urinary tract infections.Centers for Disease Control and Prevention.FAQs: About surgical site infections.Berríos-torres SI, Umscheid CA, Bratzler DW, et al.Centers for disease control and prevention guideline for the prevention of surgical site infection, 2017.JAMA Surg.2017;152(8):784-791. doi:10.1001/jamasurg.2017.0904Johns Hopkins Medicine.Septicemia.
11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Icahn School of Medicine at Mount Sinai.Surgical wound infection - treatment.Kobayashi SD, Malachowa N, Deleo FR.Pathogenesis of staphylococcus aureus abscesses.Am J Pathol.2015;185(6):1518-27. doi:10.1016/j.ajpath.2014.11.030University Health News.Pus: an unmistakable sign of infection.St. Elizabeth’s Medical Center.Abscess drainage.New York State Department of Health.Bacterial skin infections: Impetigo and MRSA.Centers for Disease Control and Prevention.Surgical site infections (SSIs).Bajracharya GR, Esa WAS, Mao G, et al.Regional analgesia and surgical site infections after colorectal surgery: a retrospective cohort analysis.Braz J Anesthesiol. 2022:S0104-0014(22)00074-4. doi:10.1016/j.bjane.2022.06.002Johns Hopkins Medicine.Urinary tract infections.Centers for Disease Control and Prevention.FAQs: About surgical site infections.Berríos-torres SI, Umscheid CA, Bratzler DW, et al.Centers for disease control and prevention guideline for the prevention of surgical site infection, 2017.JAMA Surg.2017;152(8):784-791. doi:10.1001/jamasurg.2017.0904Johns Hopkins Medicine.Septicemia.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Icahn School of Medicine at Mount Sinai.Surgical wound infection - treatment.Kobayashi SD, Malachowa N, Deleo FR.Pathogenesis of staphylococcus aureus abscesses.Am J Pathol.2015;185(6):1518-27. doi:10.1016/j.ajpath.2014.11.030University Health News.Pus: an unmistakable sign of infection.St. Elizabeth’s Medical Center.Abscess drainage.New York State Department of Health.Bacterial skin infections: Impetigo and MRSA.Centers for Disease Control and Prevention.Surgical site infections (SSIs).Bajracharya GR, Esa WAS, Mao G, et al.Regional analgesia and surgical site infections after colorectal surgery: a retrospective cohort analysis.Braz J Anesthesiol. 2022:S0104-0014(22)00074-4. doi:10.1016/j.bjane.2022.06.002Johns Hopkins Medicine.Urinary tract infections.Centers for Disease Control and Prevention.FAQs: About surgical site infections.Berríos-torres SI, Umscheid CA, Bratzler DW, et al.Centers for disease control and prevention guideline for the prevention of surgical site infection, 2017.JAMA Surg.2017;152(8):784-791. doi:10.1001/jamasurg.2017.0904Johns Hopkins Medicine.Septicemia.
Icahn School of Medicine at Mount Sinai.Surgical wound infection - treatment.
Kobayashi SD, Malachowa N, Deleo FR.Pathogenesis of staphylococcus aureus abscesses.Am J Pathol.2015;185(6):1518-27. doi:10.1016/j.ajpath.2014.11.030
University Health News.Pus: an unmistakable sign of infection.
St. Elizabeth’s Medical Center.Abscess drainage.
New York State Department of Health.Bacterial skin infections: Impetigo and MRSA.
Centers for Disease Control and Prevention.Surgical site infections (SSIs).
Bajracharya GR, Esa WAS, Mao G, et al.Regional analgesia and surgical site infections after colorectal surgery: a retrospective cohort analysis.Braz J Anesthesiol. 2022:S0104-0014(22)00074-4. doi:10.1016/j.bjane.2022.06.002
Johns Hopkins Medicine.Urinary tract infections.
Centers for Disease Control and Prevention.FAQs: About surgical site infections.
Berríos-torres SI, Umscheid CA, Bratzler DW, et al.Centers for disease control and prevention guideline for the prevention of surgical site infection, 2017.JAMA Surg.2017;152(8):784-791. doi:10.1001/jamasurg.2017.0904
Johns Hopkins Medicine.Septicemia.
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