An abscess can develop in various parts of the body. An operation may be needed to drain the pus. You may also need to take medicines called antibiotics.
What is an abscess and what causes it?
An abscess is a collection of pus. Pus is a thick fluid that usually contains white blood cells, dead tissue and germs (bacteria). The usual cause of an abscess is an infection with bacteria. Certain bacteria are more likely to be 'pus-forming' as they make chemicals (toxins) that can damage the body's tissues. These include: Staphylococcus aureus and Streptococcus pyogenes. The infection causes the immune system to activate white blood cells and chemicals to fight the bacteria. In this 'battle' some tissue dies. A cavity forms and fills with pus. The cavity becomes bigger if the infection continues.
Where do abscesses form?
The skin. Most abscesses form just under the skin. A boil is the most common example. In this case, a hair root becomes infected and develops into a small abscess. A gland just below the skin at the entrance to the vagina can get infected and develop into a Bartholin's abscess. The symptoms of a skin abscess include swelling, redness, pain and warmth over the affected area.
Inside the body. An abscess sometimes forms inside the body within an organ or in a space between organs. Various symptoms may occur, depending on the site of the abscess. Infection in the liver, for example, can result in a liver abscess. An ultrasound scan or other types of scan can confirm a suspected abscess. If infection occurs in the gums or teeth a dental abscess can develop.
Who gets abscesses?
Most skin abscesses occur in people who are otherwise well. There is often no underlying cause, and no further problems usually occur once it has gone. Your doctor may check your urine for sugar, as abscesses tend to occur more often in people with diabetes. Recurring skin abscesses may be the first indication of a problem with your immune system.
An abscess inside the body usually occurs in people who are ill with other problems, or in people whose immune system is not working well. For example, a lung abscess may form following a bout of pneumonia; a brain abscess may form after a penetrating head wound (an injury in which the outer covering of the brain is pierced), etc.
What is the treatment for an abscess?
Medicines called antibiotics are usually prescribed and the pus usually needs to be drained away. For a skin abscess, this involves a small operation to cut the top of the skin and allow the pus to drain. A scar will form as the skin heals. A more sophisticated operation is needed to drain an abscess from inside the body. The techniques vary, depending on the site of the abscess.
What would happen if an abscess were not treated?
A skin abscess would normally eventually burst on to the skin surface and let out the pus. This may be after it becomes larger and more painful. So, antibiotics and surgical drainage are usually best. However, a small boil may burst and heal without treatment. An untreated abscess inside the body is usually very serious. You are likely to become very ill and treatment is usually needed.
Further reading & references
- Drainage of superficial and deep abscesses; Surgical Tutor, 24 July 2009
- Tolan R et al; Staphylococcus Aureus Infection Clinical Presentation, Medscape, Jan 2013
- Boils, DermNet NZ, 2013
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.
Dr Tim Kenny
Dr Laurence Knott
Prof Cathy Jackson