An abcess is a localized collection of pus in any part of the body, caused by an infection.

Causes, incidence, and risk factors 
Abscesses occur when an area of tissue becomes infected and the body is able to “wall off” the infection to keep it from spreading. White blood cells, the body’s defense against some types of infection, migrate through the walls of the blood vessels into the area of the infection and collect within the damaged tissue. During this process “pus” forms, which is an accumulation of fluid, living and dead white blood cells, dead tissue, and bacteria or other foreign invaders or materials.

Abscesses can form in almost every part of the body and may be caused by infectious organisms, parasites, and foreign materials. Abscesses in the skin are readily visible and are red, raised, and painful. Abscesses in other areas of the body may not be obvious, but if they involve vital organs they may cause significant damage.

For information about a specific type of abscess see one of the following topics:

See the individual types of abscesses.

Signs and tests 
Often, a sample of fluid will be obtained from the abscess. It will be cultured to determine the organism causing the abscess. See the individual types of abscesses.

Treatment varies, but often requires antibiotics.

Expectations (prognosis) 
Most types are treatable. See the individual types of abscesses.

Calling your health care provider 
Call your health care provider if you think that you may have any type of abscess.


Prevention of abscesses is dependent on the location and cause. For example, good hygiene is important in prevention of skin abscesses. Dental hygiene and routine care will prevent dental abscesses.

Johns Hopkins patient information

Last revised: December 5, 2012
by Potos A. Aagen, M.D.

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