A localized collection of pus in any part of the body that is the result of 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 and 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 ( necrotic ) tissue, and bacteria or other foreign invaders or materials. Abscesses can form in almost every part of the body and may be caused by bacteria, parasites, and foreign materials. Abscesses in the skin are readily visible, 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:

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

Treatment varies, but often requires antibiotics. See the individual types of abscesses.

Expectations (prognosis)

Most types are treatable. See the individual types of abscesses.

Complications

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

Prevention of abscesses is dependent on the location and cause. Good hygiene is important in prevention of skin abscesses. Dental hygiene and routine care will prevent dental abscess . A recent rise in unusual bacterial and fungal abscesses including brain abscesses has occurred with the increased use of illegal intravenous drugs. Hygiene, sterility, and safety are often not concerns at the time the drugs are being used. Avoiding intravenous drug routes will remove this cause of avoidable abscesses.