An abscess is a localized collection of pus in any part of the body that is surrounded by swelling (inflammation).

Abscesses occur when an area of tissue becomes infected and the body's immune system tries to fight it. White blood cells move through the walls of the blood vessels into the area of the infection and collect within the damaged tissue. During this process, pus forms. Pus is the build up of fluid, living and dead white blood cells, dead tissue, and bacteria or other foreign substances.

Abscesses can form in almost every part of the body and may be caused by infectious organisms, parasites, and foreign substances. Abscesses in the skin can be easily seen, and are red, raised, and painful. Abscesses in other areas of the body may not be obvious, but if they may cause significant organ damage.

Specific type of abscesses:

• Amebic liver abscess
• Anorectal abscess
• Bartholin's abscess
• Brain abscess
• Epidural abscess
• Peritonsillar abscess
• Pyogenic liver abscess
• Skin abscess
• Spinal cord abscess
• Subcutaneous abscess
• Tooth abscess

Often, a sample of fluid will be taken from the abscess and tested to see what organism is causing the problem.