Surgery Recovery What Is Pus? Thick Fluid That Is a Sign of Infection By Jennifer Whitlock, RN, MSN, FN linkedin Jennifer Whitlock, RN, MSN, FNP-C, is a board-certified family nurse practitioner. She has experience in primary care and hospital medicine. Learn about our editorial process Jennifer Whitlock, RN, MSN, FN Medically reviewed by Medically reviewed by Scott Sundick, MD on October 01, 2020 linkedin Scott Sundick, MD, is a board-certified vascular and endovascular surgeon. He currently practices in Westfield, New Jersey. Learn about our Medical Review Board Scott Sundick, MD on October 01, 2020 Print Table of Contents View All Function Types Causes Treatment Prevention Pus is a thick fluid matter produced as part of the body's inflammatory response to an infection. It consists of a buildup of degenerating white blood cells, dead or living bacteria (or other microorganisms), and tissue debris. Pus is typically an opaque white-yellow color but can be tinted brown or even green. It's usually odorless although certain types of bacteria produce foul-smelling pus. The medical term for pus is purulent exudate. It is also sometimes called purulent drainage, and the fluid is sometimes referred to as liquor puris. A small amount of pus, such as from pimples, typically isn't a cause for alarm, but pus at the site of a wound, surgical incision, or deep interior location may require medical intervention. Treatments for infections with pus may include antibiotic medications, drainage procedures, or surgical removal of infected tissues. Pus is a thick, white substance that's typically a sign of infection. The medical term for pus is purulent exudate. It is also sometimes called purulent drainage; the fluid is sometimes referred to as liquor puris. Function Pus is an indication your body has started to combat infection by sending infection-fighting cells to the area. Pus is often part of an abscess, a collection of pus in a cavity formed from the breakdown of infected tissues. Abscesses can happen just under the skin or anywhere in the body and typically are the result of bacteria such as Streptococcus or Staphylococcus aureus gaining access to tissues, such as through a small opening in the skin. Fungus or parasites can also lead to abscesses. Once the bacteria or other microorganism starts multiplying, they release toxins that destroy cells. This triggers an immune response in which leukocytes (white blood cells) head to the site to kill and absorb the bacteria and break down the dead tissue. During this process, white blood cells also break down and die, forming the pus. Types Pus can be visible on the surface of the skin or it may form internally as a complication of an infection or injury. Skin Infection Types of skin conditions characterized by pus on or just beneath the skin's surface include: Acne: Pores clogged with oil and debris form pimples or pustules on the skin's surface that contain pus.Folliculitis: Small acne-like bumps from infected hair folliclesBoils or furuncles: Painful nodular bumps from infected hair follicles that are typically caused by Staphylococcus aureusCarbuncles: A group of connected boilsSuperficial surgical site infection (SSI): An SSI is at the skin level only, where pus can form along the incision, which may become red and painful when touched.Trauma wounds: Pus and yellow crust at the site of a wound caused by injury or physical trauma may be accompanied by pain or swelling. Learn About Some of the Most Common Bacterial Skin Infections Internal Infection Pus-filled abscesses can form internally, such as in the mouth or alongside internal organs. It can be a result of a surgical complication, injury, or untreated bacterial or fungal infection. There are many types of internal abscesses and conditions that can lead to pus, including: Abscessed tooth: A dental infection in or near the root of a toothDeep SSI: An infection can occur internally in muscles and other tissues or may form in the organ or area of the surgeryPeritonsillar abscess: Spots of pus at the back of the throat or behind the tonsils can form as a symptom of strep throat or tonsillitisEmpyema: A collection of pus in the pleural space between the lungs and the chest wall that can be a complication of bacterial pneumonia or lung surgeryBrain abscess: A rare swelling of pus in the brain that can be caused by a bacterial or fungal infectionSeptic arthritis: A serious joint infection that can form after bacteria travels through the bloodstream to the joint Causes Punctures, scrapes, scratches, or other openings in the skin can allow bacteria that live on the skin to enter the body and cause an infection. This includes surgical incisions. There can also be deep internal infections with pus that occur after surgery, injuries, or illnesses. There are certain factors and underlying conditions that can put you at risk for infections and wound complications with pus: Poor hygiene, such as not washing your hands before touching a woundDiabetesOlder ageSmokingSevere obesityAn immune system disorder, HIV infection, or cancerMedications that reduce immune system activity, such as corticosteroids or immunosuppressantsParalysis or limited mobilityLow body temperatureLong operations and hospitalizationEmergency procedures For people who have compromised immune systems, pus may never form in an infected area, but most will find that infection leads to discharge from the area as well as the possibility of redness, pain or tenderness, swelling, and fever. Treatment Most SSIs and skin wounds are treated with oral antibiotics or ointments. Antibiotics are important because they help the body heal faster and may prevent an infection from becoming worse. Laura Porter / Verywell Your physician may collect your wound drainage and send it to a lab to determine what type of bacteria is causing the infection. This process, called a culture and sensitivity test, can be used to determine which antibiotic the bacteria is sensitive to and may kill the bacteria most efficiently. Cultures Used for Diagnosis For post-surgery pus, your physician may recommend a special incision care program and may want to see your incision in order to make sure there isn’t an underlying problem. In some cases, an abscess drainage procedure to remove pus or surgical debridement (removal of dead tissue) may be needed to address the infection. In cases of sepsis, a dangerous and life-threatening condition in which an infection enters the bloodstream and can spread throughout the body, hospitalization will be required. Prevention There are simple things you can do to reduce your risk of developing an infection with pus: Wash cuts and other wounds gently with soap and waterFollow your physician's care instructions after surgery or hospitalization for injuriesWash your hands thoroughly and regularlyDon't squeeze pus out of pimples or boils. Instead, gently apply a warm compress several times a dayDon't share towels or razorsEat a healthy, balanced dietBe vigilant about controlling your blood sugar control if you have diabetesQuit smoking Aggressive scrubbing of infected skin can do more harm than good because an irritated wound becomes infected more easily and will also be more tender or even painful. The same goes for lesions such as pimples or boils. Treat any skin condition as gently as you would a baby's behind. Preparing for Surgery Between 1% and 3% of people who have surgeries develop an infection, according to the Centers for Disease Control and Prevention. There are steps you can take before and after any procedure to reduce your risk of an SSI. Before Surgery The night before surgery, wash your whole body with soap in the bath or shower. Do not shave near the area where the surgery will be since it can irritate the skin and make you more prone to infection. (Your doctor may use electric clippers just before surgery to clear hair from the region.) After Surgery Family or friends should always wash their hands before visiting and should not touch the wound unless they are the person caring for your wound Follow instructions for wound care during and after leaving the hospital Always wash your hands before and after caring for the wound Most surgical infections occur within a month. During this time, inspect your incision daily for signs of infection. Do not scrub your incision, slather it with antibiotic ointment, or clean it with alcohol or peroxide unless instructed to do so by your physician. Keep the incision dry and protect it with a clean bandage. You can leave it uncovered, but if drainage leaks 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. Learn How to Care For Your Incision After Surgery When to Call Your Doctor Always contact your doctor if you see pus, especially after physical trauma or surgery, or have any redness or pain with a wound since these are all signs of infection. 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 any cloudy or white-yellow drainage, it should be promptly examined by a healthcare provider. This 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 physician or surgeon should be a priority. If you have a wound or surgical incision and experience any flu-like symptoms, even without pus, seek urgent medical care. Untreated infections can put you at risk of serious or even life-threatening conditions, such as sepsis, and should not be ignored. Warnings Signs Seek urgent medical care if you have any of the following symptoms of an SSI or sepsis:Redness and pain at a wound or surgery siteCloudy drainage from a wound or incisionFeverConfusion or disorientationShortness of breathHigh heart rateShiveringExtreme pain or discomfort orClammy or sweaty skin A Word From Verywell One of the most important things you can do to avoid an infection with pus is to wash your hands often. This is crucial before and after caring for skin bumps, incision, or wounds. If it is too late to prevent an infection, follow guidance from your physician so you can promote healing and minimize tissue damage and complications. If you have a wound, plan to take the time to clean it appropriately, check the wound regularly for any signs of infection, and be sure to protect it when necessary. Was this page helpful? Thanks for your feedback! Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Pisetsky DS. Pus: the Rodney Dangerfield of immunology. Arthritis Res Ther. 2011;13(5):131. doi:10.1186/ar3477 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 Centers for Disease Control and Prevention. Surgical site infections (SSIs). Updated November 20, 2010. Centers for Disease Control and Prevention. Skin infections. Updated May 22, 2020. 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 Centers for Disease Control and Prevention. What is sepsis? Updated August 27, 2019.