Pus

What is pus?

Pus is a pale-colored fluid that forms after your immune system responds to a possible threat. It consists of certain types of dead or dying immune cells, diseased or dead tissue (necrosis) and tissue fluids.

When your immune system detects a possible intruder, it sends immune cells like white blood cells to investigate. They attack anything they think doesn’t belong. And damaged or diseased cells start to break down. Once the dead or diseased cells are out of the way, your body can replace them and repair the damaged tissues.

Those dead or dying cells leave behind small empty spaces. Inside those spaces, leftover dead tissue and fluids mix with two specific types of white blood cells to form pus. Those cells, neutrophils and macrophages, usually give pus its color. But pus can also have slight color differences from other fluids or substances that mix in.

Pus tends to stay in one place underneath your skin or even inside your body. But if the space holding the pus breaks open, the pus can drain (called purulent drainage).

Colors and smells

Pus can have the following colors:

• Milky or yellow. It’s common for pus to appear white or milky-colored with a yellowish tinge to it.
• Pink. This can happen when blood mixes in with the pus. Some infections may cause this color, too.
• Green. This can happen with certain types of bacteria like Pseudomonas aeruginosa. Green pus always needs treatment by medical professionals.
• Brown. Pus can take on a brownish tinge because of dead tissue or old blood.

Pus can also be odorless or have different smells. If it smells yeasty, sour or foul, it needs professional medical attention as soon as possible.

What causes pus?

Pus always happens because of an immune response. The most common reason for this kind of response is a bacterial infection. But fungal, parasitic and even viral infections can cause it to form, too. And while it isn’t common, pus can also form without infections.

Depending on how and where pus forms or the condition causing it to develop, it might get a specific name. Examples include:

• Abscesses
• Acne papules or pimples, also known as pustules (whiteheads) if pus collects at their top
• Boils or carbuncles
• Hypopyon (pus inside the anterior chamber of your eye)
• Kerions (from fungal infections)

Some other specific conditions that can cause pus to form include:

• Cellulitis
• Empyema
• Felon finger
• Granuloma-related conditions like granulomatosis with polyangiitis (GPA)
• Impetigo
• Inflamed hair follicles (folliculitis)
• Inflammatory bowel disease (which can cause pus in your poop)
• Pustular psoriasis
• Pyoderma gangernosum and other autoimmune diseases.
• Pyomyositis (muscle infection)
• Rosacea

How is pus treated?

The treatments for pus mainly depend on what causes it, where it is and how much there is. Your body can gradually break down pus and reabsorb its components. That’s why small accumulations of pus (like in a pimple) often don’t need treatment.

But pus may need treatment if any of the following are true:

• If you have pus because of an infection (which can spread and cause dangerous complications like sepsis)
• If the pus or other discharge is coming from a surgical incision or similar spot on your body
• If the pus is coming from your eyes, ears or genitals, or someplace around them
• If the amount of pus is large enough that it will take a long time or is unlikely to heal properly
• If it’s in a location where it could cause serious or dangerous complications
• If it’s happening because of a chronic (long-term) condition

The most common treatments for pus include:

• Medications. Antibiotics are the mainstay for treating bacterial infections. They don’t treat other types of infections, but antifungal or antiparasitic medications may.
• Drainage. Providers may be able to reach shallower accumulations of pus through a small incision. Once they do, they can drain the pus out, making it easier for the site to heal.
• Surgery. Larger wounds that either get infected or remain after an infection may need surgery to drain and repair.
• Specialized wound care. Larger wounds that are slow to heal may need more specialized types of care. These can include wound drains and hyperbaric oxygen therapy.

Because pus has so many potential causes and treatment options, your safest choice is to talk to a healthcare provider about it. The information they can provide will be most relevant to your specific case.

What can I do at home to treat pus?

You can self-treat pus when it happens in very small amounts and in small wounds. If it’s an open wound, keep it clean and bandaged until it scabs over. Pimple patches or other types of treatments may be all you need for small skin changes that do or could contain pus.

But if a wound or pus-containing spot is slow to heal or gets larger, talk to a healthcare provider. A primary care provider or urgent care clinic can usually provide the care you need.

What not to do

There are a few things you shouldn’t do if you have a wound or skin change that could contain pus.

• Never use something to puncture it. Using a sharp object to poke a hole in a skin change or pustule can lead to severe infections.
• Don’t pop it. This is especially true when the pus could be in a skin change in the danger triangle of your face. Infections here can spread easily and become life-threatening.
• Don’t assume antibiotics or similar treatments are the answer. Antibiotics do nothing for nonbacterial infections. And antibacterial products like bacitracin or neomycin ointments may actually irritate your skin. Talk to a healthcare provider before you use over-the-counter products.

What are the possible complications or risks of not treating pus?

Pus is usually a sign of an infection. Infections can cause wounds that grow and damage more and more surrounding tissue. Larger wounds can take longer to heal and may scar.

And if infections spread to your bloodstream, they can cause an overwhelming immune reaction called sepsis. That condition is a life-threatening medical emergency.

If you’re concerned about possible complications or risks with your case, talk to your healthcare provider. They can tell you more about what’s most likely for your situation.

Can pus be prevented?

Conditions that can cause pus to form aren’t always preventable. But there are a few things you can do to lower your risk. They include:

• Wash your hands. Handwashing is the best way to prevent infections that could lead to pus forming. If your hands are visibly dirty or soiled, use soap and water. If your hands look clean, you can use alcohol-based hand sanitizer (as long as it’s at least 60% alcohol).
• Treat minor wounds properly. Use soap and water to clean smaller open wounds and then cover them with a bandage.
• Get prompt care for wounds that need expert attention. Don’t try to self-treat wounds that need professional care.

When should pus be treated by a doctor or healthcare provider?

Pus needs expert medical care when an infection could be the cause. You should also get medical care right away for a wound with pus if you also have the following:

• A fever. Having a temperature above 101 degrees Fahrenheit (38.3 degrees Celsius) and a wound with pus could signal a worsening infection or sepsis.
• The skin around the wound is warm to the touch. If skin around the wound is warmer than skin farther away, that’s a key sign of infection.
• If the pus is green or has a noticeable smell. These are both signs of certain types of infections.
• If the wound isn’t healing after a few days or gets larger. Wounds that are slow to heal should get professional care.
• If you have severe pain around the wound. You need medical attention if you have pain that’s much worse than what you’d expect based on how a wound looks.
• If color changes around a wound spread. For example, if there’s spreading redness or red streaks. That could be a symptom of a worsening infection.

Is it OK to squeeze out pus?

Squeezing out pus from smaller skin changes like pimples is often tempting. But if you can avoid it, don’t do it.

Don’t squeeze out pus from larger spots like boils or open wounds. A medical professional should be the one to provide that kind of care. Letting them handle it is the best way to avoid worsening infections and other complications.

Does pus mean infection or healing?

Experts once believed that pus could be a sign that a wound was healing and saw it as a good thing. Today, experts know pus usually isn’t a good thing. If you have concerns about having it, the best thing you can do is talk to a healthcare provider sooner rather than later.