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Date issued: December 2022 

Review date: December 2024

Ref: A-512/NB/ED/Abscess

PDF:  Abscess final December 2022.pdf [pdf] 89KB

What is an abscess and what causes it?

• An abscess is a collection of pus. The usual cause of an abscess is an infection with bacteria. The infection causes the immune system to activate white blood cells and chemicals to fight the bacteria.

• A cavity forms and fills with pus. The cavity becomes bigger if the infection continues. An abscess is painful, and patients often have a temperature.

Where do abscesses form?

• The skin. Most abscesses form just under the skin. A boil is the most common example. The symptoms of a skin abscess include swelling, redness, pain, and warmth over the affected area.

• Common sites are the fingers, armpit, fingers, breast, and groin.

• Abscesses can occur in other parts of the body, e.g., dental abscesses. This information sheet does not refer to these abscesses.

Who gets abscesses?

• Most skin abscesses occur in people who are otherwise well. There is usually no underlying cause, and no further problems usually occur once it has gone.

• Your doctor may check your urine for sugar if you continue to get abscesses as they tend to occur more often in people with diabetes.

• Recurring skin abscesses may be the first indication of a problem with your immune system

What is the treatment for an abscess?

• 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. This may need either a local or general anaesthetic depending on the size and location. A scar will form as the skin heals.

• Most abscesses do not need antibiotics: drainage of the pus is sufficient. However, antibiotics are sometimes required.

• Antibiotics will usually be required if you have an artificial heart valve or some other heart conditions or if you have an artificial joint.

What would happen if an abscess was not treated?

• A skin abscess would normally eventually burst onto the skin surface and let out the pus. This may be after it becomes larger and more painful. So, surgical drainage is usually best. However, a small boil may burst and heal without treatment.