• Overview


An abscess is a painful collection of pus  caused by a bacterial infection. 

This article focuses on two types of abscess:

  • skin abscesses  which can develop anywhere on the body and occur when a bacterial infection causes pus to collect in the skin
  • internal abscesses  which develop inside the body following an infection or an injury

The symptoms of an abscess can vary depending on which type you have.

A skin abscess is often painful and appears as a swollen, pus-filled lump under the surface of the skin, or an open break in the skin.

It's more difficult to identify an abscess inside the body, but signs include pain in the area, a high temperature and generally feeling unwell.

What causes an abscess?

Most abscesses are caused by a bacterial infection.

When bacteria enter your body, your immune system sends infection-fighting white blood cells to the affected area. As the white blood cells attack the bacteria, some nearby tissue dies. A hollow then develops and fills with pus to form an abscess.

Most skin abscesses are caused by an infection in the root of a hair or by a blocked sweat gland. They usually affect people who are otherwise well.

It may be possible to help prevent a skin abscess through good hygiene, a healthy lifestyle and looking after your skin.

Internal abscesses often develop as a complication of an existing condition. Those with an underlying health condition or weakened immune system are more likely to get internal abscesses.

Read more about the causes of an abscess.

Treating an abscess 

A small skin abscess may drain naturally, or simply shrink, dry up and disappear without any treatment.

Larger abscesses may need to be treated with antibiotics to clear the infection and surgery to drain the pus. Without treatment, an abscess may continue to get larger and more painful until it eventually bursts.

Read more about how an abscess is treated.

Other types of abscess

There are a number of other types of abscess not fully covered in this article including:

  • dental abscess  a build-up of pus inside a tooth that is caused by a bacterial infection
  • brain abscess a rare but potentially life threatening build-up of pus caused by bacteria following trauma to the skull, after surgery or from a previous infection
  • Bartholin’s cyst  a build-up of pus from one of the Bartholin’s glands, found on each side of the opening of the vagina
  • a liver abscess  caused by an abdominal infection, such as appendicitis, a blood infection or an infection of the passages that transport bile around the body (the biliary tracts)
  • a spinal cord abscess caused by an infection inside the spine that results in inflammation (swelling) and a build-up of pus around the spinal cord
  • an anorectal abscess  a collection of pus that builds up in the rectum and anus due to a sexually transmitted infection (STI), a blocked gland or infection of an anal fissure (a tear or ulcer in the lining of the anal canal)
  • a peritonsillar abscess  the most common infections of the head and neck region and usually a result of tonsillitis (an infection of the tonsils)

Page last reviewed: 17/07/2012

Next review due: 17/07/2014


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