Seeing pus coming from any area of your body can be frightening, no matter the color. And while leaking pus may be a symptom of hidradenitis suppurativa (HS), that’s not the only cause of pus.

Other types of wounds and infections may produce pus as well. Keep reading to discover when you might encounter pus in general, as well as while dealing with HS. Plus, find information on whether pus color has any bearing on whether a wound might be infected or not.

What Is Pus?

Pus is a fluid that can form in your body after it responds to a threat, such as an infection or HS flare. In most cases, when your body believes something is trying to intrude and cause damage, it responds by sending white blood cells and other immune cells to attack the foreign invaders. These immune cells damage the intruder cells.

Your immune system then begins replacing the damaged cells and dead tissue with healthy cells and tissue. This leaves behind the damaged tissue and cells, which then blend with certain white blood cells called macrophages and neutrophils, forming pus. Simply put, pus is a byproduct of the body fighting infection.

In many cases, your body will reabsorb pus that doesn’t drain from a wound and you’ll never see it. But if the skin breaks over an area where pus forms, pus may ooze out and be visible.

When pus drains from a wound, it’s referred to as purulent drainage.

Serous Drainage vs. Purulent Drainage

Pus isn’t the only type of fluid that may drain from a wound. Besides blood, you may see three types of wound drainage come out of your skin. Some, but not all, may be a normal part of the healing process. The most common are serous drainage and purulent drainage.

• Purulent drainage — This thick pus comes out of a wound in the skin, typically signifying an infection.
• Serous drainage — This clear or yellow-tinged fluid is nearly the consistency of water. You may see it left on a bandage that covered a healing wound.
• Serosanguineous fluid — This is serous drainage mixed with small amounts of blood, making it a light pink color. You may see it on wound dressings after covering a new injury to the skin.

Serous and serosanguineous fluids are both considered a normal part of the wound healing process — unless the amount of drainage seems excessive.

If you’ve already been diagnosed with HS, you may be able to identify HS discharge. If so, you’ve likely established a strategy to manage HS discharge, and you should follow the treatment plan your dermatologist recommended.

If you’ve never been diagnosed with HS, seek medical advice if you see pus on your skin.

Identifying HS Drainage

HS lesions are caused by inflammation rather than infection, although secondary bacterial infections can follow. HS abscesses may look similar to an infection due to the open skin and pus drainage. Because the treatment for an HS flare-up is different from treatment for an infection, and because HS and infection can sometimes coexist, it’s important to understand what you have.

There’s no single test that can identify whether you’re experiencing HS versus an infection. If you’ve never been diagnosed with HS and you see pus on your skin, get medical help from your primary care provider. A dermatologist is the most appropriate person to identify HS and help you create a treatment plan tailored to meet your needs.

A healthcare professional can ask about your medical history to see if you’ve had itching, sore lumps or bumps, or other early HS symptoms. They might also take a sample of your wound drainage to see if it’s bacterial or not. In some cases, HS leakage doesn’t have bacteria in it.

What Pus Color Indicates an Infection?

If you don’t have HS, it’s important to see a doctor about any pus drainage because it could be a sign of infection.

For people diagnosed with HS, it may be more challenging to identify an infection. For instance, pus accompanied by a foul smell may be a sign of a worsening infection in those without HS. But for people with HS, wound drainage with odor is often considered normal.

For that reason, it’s a good idea to know what different pus colors may mean. Though these won’t always be a sure sign of how your wound is progressing, they may be helpful as a guideline.

• White pus — Typically means the infection is moving in the right direction, but treatment may still be necessary
• Yellow pus — May indicate that a bacterial infection is present, such as staphylococcus
• Green pus — May be a sign of a bacterial infection
• Pink or red pus — Usually indicates that blood is mixed with pus in the wound
• Brown pus — May be a sign of liver infection

Always talk to a doctor about any concerning wound drainage. Bacterial infections require treatment with medications like antibiotics, and liver infections require a specialist to diagnose and treat them.

“Currently up with a flare-up,” one myHSteam member wrote. “One of the five areas has decided to burst and has a slowly oozing, almost mint-green color. Should I go to the hospital?” Another member replied, “Always best to get it checked out.”

If you have HS and you’re concerned you may have an infected wound, call your doctor or go to a hospital.

Signs of Wound Infection With HS

In addition to pus changing color, other symptoms may indicate you’re experiencing an infection. Bacterial skin infections are typically diagnosed using the term cellulitis.

“I was in the hospital for Thanksgiving because of cellulitis — I needed intravenous antibiotics. I was surprised how much it helped with the inflammation and pain,” one myHSteam member wrote.

Another member said, “I've been in the hospital several times with cellulitis. The last infection landed me in the ICU for two days. The important thing with cellulitis is to go to the doctor as soon as you notice something irregular.”

Cellulitis symptoms may include:

• Tender skin that’s even sensitive to light friction
• Skin that feels warm to the touch
• Redness or discoloration and swelling that expands over time
• Discoloration and streaks that start at the affected area and move outward
• Fever

Any of these symptoms may indicate cellulitis and require immediate medical attention and antibiotics. It’s important to begin treatment quickly to prevent the further spread of bacteria in the blood. If untreated, cellulitis can become generalized sepsis, so always contact your doctor if you notice any of the above symptoms.

Find Your Team

If you or a loved one is living with HS, consider joining myHSteam today. Here, more than 46,000 members from around the world come together to ask questions, offer support and advice, and connect with others who understand life with hidradenitis suppurativa.

Have you experienced a wound infection while living with HS? Did pus color indicate a sign of infection at the time? Share your experience in the comments below or by posting on myHSteam.