What is Pus?

Pus. Just the mere mention of that word is enough to make some people feel a little queasy. To make matters worse, pus generally shows up during an infection, which may already be causing a person to feel sick or be in pain. And yet, the presence of pus is a good sign that your body is working hard to help you overcome an attack by invaders. Doesn't that make you feel better?

A description of pus

Most people know what pus looks like. While it's usually pale yellow or white in color, pus can actually come in a rainbow of colors, from green to brown to reddish. It can be thick and sticky or a bit watery. It can have a foul odor or it might not smell at all. Dictionary.com defines pus as a "generally viscous, yellowish-white fluid formed in infected tissue, consisting of white blood cells, cellular debris, and necrotic tissue." But how did that fluid get there?

A scenario

Say you're walking down a sidewalk one day and you trip and fall on your knee. Embarrassed, you stand up quickly, only to notice that your knee is bleeding from a cut caused by a small piece of broken glass. Your knee smarts as the blood oozes from the cut. You sit down on the curb and use a tissue to wipe away the blood. The process of bleeding is one way your body is already starting to take care of the damage you sustained when you fell. The blood helps carry some of the dirt and debris away from the break in your skin.

As the bleeding slows down, you can see the skin around your cut turning reddish and growing warm. The inflammation process has begun. When you cut your knee, your body responded by releasing certain chemicals to both start to repair the wound and to protect the surrounding, undamaged tissues. However, despite your body's best efforts to keep germs out, the cut is invaded by microorganisms. You don't have time to clean out your cut. You rush off, planning to take care of that cut when you have more time... but you forget and your cut gets infected.

Infection

Your body is equipped with a number of remarkable defenses that keep microorganisms at bay. But sometimes germs can still break through your natural barriers and cause an infection. A superficial wound is one way an infection can get started.

A couple of days after you cut your knee, you notice that your knee is still very tender and warm to the touch. The skin is red and angry looking and it hurts to move your knee. Looking at the scab that has formed over the cut, you can see a sticky brownish fluid. You know that's pus.

When your body detected the presence of an invader, it sent an army of certain white blood cells to the site of the injury to launch a counter attack. The white blood cells arrived on the scene ready to do battle with the germs that managed to break through the surface. The specific white blood cells on hand are called neutrophils and they start to engulf and kill the bacteria that has taken up residence in your cut. But after about twelve hours or so, the neutrophils start to die. That's when they are further broken down by another white blood cell called a macrophage.

As the macrophages do their work, pus begins to form. It's made up primarily of dead skin cells, live and dead white blood cells, and living and dead bacteria. Your valiant immune system is fighting the invader and (hopefully) winning!

What should you do when you see pus?

The sight of pus, in and of itself, is not usually a cause for alarm. For a minor wound, you can simply clear away the pus by cleaning it with a gentle soap and water or using some antiseptic. However, sometimes wound infections can be serious and require the attention of a health care professional. The following signs and symptoms of wound infection should prompt you to get medical help:

* Fever
* Increased discharge of blood or pus, particularly if it has a bad smell
* Increased swelling, warmth, and redness around the wound that doesn't go away after a few days
* Increased pain
* An old wound that bleeds easily
* A pain that doesn't look like it should be painful, but is

Your health care provider will likely take a look at the wound and perhaps draw blood or take a wound sample. If need be, he or she may also take some images using x-ray, computer tomography (CT), magnetic resonance imaging (MRI), or a bone scan. Treatment of the wound infection will mostly depend on what type of microorganism caused it and how severe it is.

Pus is...

Pus is certainly a disgusting sight to many people, but it is a necessary part of your body's ability to fight off invaders. The next time you get an infection and see a little pus formation, maybe you'll remember it's just a part of your body's amazing ability to protect itself from invaders.

Sources:

www.dictionary.com
www.wisegeek.com
www.drugs.com