Purulent Drainage: Understanding The Causes, Symptoms, And Treatment Options

Dr bandaging foot female patient

Wound drainage, commonly known as exudate, is a natural part of the healing process in the human body. It is the body’s response to tissue damage in the form of fluid production. The nature and composition of the drainage depend on the severity of the wound.

What is purulent drainage?

Purulent drainage is a thick, milky white discharge indicating an unhealthy wound or infection. It requires immediate medical attention. Sometimes the fluid can vary in colour – yellow, green or brown – accompanied by a foul, pungent or musty odour.

Easily spotted, the discharge is the secretion of various dead cells, bacteria, and white blood cells trying to fight the infection. Any significant change in the colour or odour indicates the progression of infection. It can be a cause of concern and require medical attention.

Symptoms of purulent drainage

All wounds also have a peculiar odour, consistency. The colour of the wound depends upon the bacteria surrounding them. Some wounded areas can secrete pale, light drainage which is normal.

Healthcare professionals must look for the following signs that can indicate purulent drainage in a wound:

  • Thick consistency: Normal drainage is pale or sticky with thin consistency. On the other hand, an infected wound has thick drainage.
  • Milky appearance: Normal wound drainage is pale or has a hue. Purulent drainage is thick, milky, and even changes colour if the infection progresses.
  • Green, yellow, brown or white colour: A wound exhibiting purulence is plagued with pus – a sign of infection. If the pus appears to be green, yellow, brown or milky white in colour, it indicates a progression of infection.
  • Distinct odour: Most wounds have a peculiar smell. However, a foul, pungent or strong odour indicates purulent drainage.

Causes of purulent drainage

When a site is wounded, the body sends white blood cells and other components to start the healing process and kill any incoming germs. These components form a protective layer around the wound. When the germs penetrate this barrier, they multiply and cause an infection.

Infected wounds turn purulent because of the bacteria present in the skin, external environment, or other parts of the body. It results in further tissue damage and prolongs the healing process.

The infection depends on several factors such as the location of the wound, its size, temperature, hydrostatic pressures, type of wound, and dressing. Patients with diabetes, vascular disease, or neuropathy are at higher risk of purulent drainage.

Treatment for purulent drainage

It is crucial to treat wounds that have turned purulent to avoid further medical complications. Treatment options can vary based on the size, location, stage of wound healing, and overall health of the patient.

Two steps are key in treating such wounds – preventing further drainage and keeping the area moist to avoid contamination.

Types of dressing and cleansing methodology can vary depending on the kind of infection. Risk assessment becomes a crucial part of finalising the treatment plan. Wounds with venous insufficiency require elevation and compression to manage drainage. Deeper or chronic wounds sometimes require negative pressure wound therapy.

Doctors can sometimes prescribe antibiotics for the infection, which can aid the healing process. If an abscess develops (pus build-up on the injured site), a healthcare professional can drain it. If the infection reaches the next stage (begins to spread to other parts of the body) or turns septic, hospital admission is required.

Types of wound drainage

  • Serous purulent drainage: Mainly composed of white blood cells, it is thin and pale in appearance. Serous drainage appears in the initial 48-72 hours of an injury during the inflammatory wound healing stage.
  • Sanguineous: Mostly composed of fresh blood, it is pink or bright red in colour. It occurs during the initial few hours of an injury.
  • Serosanguineous: With a combination of serous and sanguineous drainage, serosanguineous is the most common type of discharge. It is usually pale and thin in appearance with a reddish tinge.


Paying close attention to a wound as it heals is key to managing the purulent drainage. A distinct assessment of the exudate appearance and volume indicates a lot about the healing process to the healthcare professional. Detecting complications in the initial stage while providing correct treatment may further aid healing.


Q: Which type of dressing is best for purulent drainage wounds?
A: Purulent wounds require dressings that trap the exudate and balance the moisture in the wound site. Alginate dressings contain seaweed fibres and sodium, which absorbs excess liquid and form a gel that aids the healing process. These dressings should be changed every two days.

Q: How do you stop a wound from exuding pus?
A: The only way to avoid a wound from exuding pus is to ensure that it does not get infected. Keeping the wounded site clean and regularly dressing the site can help prevent pus formation. Healthcare professionals can surgically drain pus-filled wounds to aid the healing process.

Q: What colour pus is bad?
A: Pus is a protein-rich fluid known as liquor puris, which is accumulated at the site of infection. While whitish-yellow pus is normal, pus with the colour yellow, green or brown along with a foul smell can be a sign of infection.

Q: What does wound exudate look like?
A: Exudate or drainage that comes out of a wound is thin and watery in appearance. When accompanied by blood, it appears slightly pink or red. If the exudate is thick, milky white with a yellow, green, or brown appearance, then the wound is purulent.

Q: What is the difference between pus and mucus?
A: While pus or drainage is whitish-yellow in appearance, it consists of dead cells, bacteria, and white blood cells. On the other hand, mucus or phlegm is a viscid fluid secreted by mucous membranes.

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