Abscess - Causes 

  • Overview

Causes of an abscess 

Most abscesses are caused by a bacterial infection. However, they can very occasionally develop due to an infection by viruses, fungi or parasites.

When foreign organisms such as bacteria enter the body, the immune system sends white blood cells to fight the infection. This causes swelling (inflammation) at the site of infection and the death of nearby tissue, creating a hole called a cavity, which fills with pus to form an abscess.

The pus contains a mixture of dead tissue, white blood cells and bacteria. The abscess may get larger and more painful as the infection continues and more pus is produced.

Most abscesses occur as a result of staphylococcal bacteria and streptococcal bacteria.

Some types of staphylococcal bacteria produce a toxin called Panton-Valentine leukocidin (PVL), which kills white blood cells. This causes the body to make more cells to keep fighting the infection, and can lead to repeated skin infections.

Read about the symptoms of staphylococcal infections.

Skin abscesses

When bacteria gets under the surface of your skin, an abscess can form. This can occur anywhere on the body, although skin abscesses tend to be more common in the:

  • underarms
  • hands and feet
  • trunk
  • genitals
  • buttocks

Bacteria can get into your skin and cause an abscess if you have a minor skin wound, such as a small cut or graze, or if a sebaceous gland (oil gland) or sweat gland in your skin becomes blocked.

Internal abscesses

Abscesses that develop inside the tummy (abdomen) are caused by an infection reaching tissue deeper within the body. This can occur as a result of:

  • an injury
  • abdominal surgery
  • an infection spreading from a nearby area

There are many ways an infection can spread into the abdomen and cause an abscess to develop.

For example, a lung abscess can occur due to a bacterial infection in your lungs, such as pneumonia, and a burst appendix can spread bacteria within your abdomen.

Increased risk

In addition to the specific causes mentioned above, things that increase the likelihood of an abscess developing can include:

However, many abscesses develop in people who are otherwise generally healthy.

Page last reviewed: 24/07/2014

Next review due: 24/07/2016


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The 3 comments posted are personal views. Any information they give has not been checked and may not be accurate.

Becs1234 said on 08 April 2013

I was diagnosed with Hidradenitis Suppurativa in September 2011. I had some success treating this with antibiotics. When they didn’t work I was plagued with boils and at times had 20 boils in my armpits. I also ended up with 3 boils on my face which caused my face to swell up. It was incredibly painful and made me desperate and miserable.
There didn’t appear to be any specific guidelines for how doctors should approach this treatment as the guidance stated that the treatment plan should be tailored to the individual. I am assuming that this is because some antibiotics work for some people but not for others.
Personally I found it really helpful to do my own research and I sought a second opinion as my dermatologist would not prescribe me the latest combination drug therapy.
I spoke to a number of doctors regarding their treatment plans and in the end selected a fantastic doctor in Cardiff (a bit of a trek from Leeds). I had photographed all of my symptoms and showed this to the doctor as well as an infection I had at the time.
I am a very active person and he said that this did not fit with Hidradenitis Suppurativa and that facial boils were not normally associated with this disease. He diagnosed me as having PVL Staphylococcus Aureus which is a community acquired MRSA. The GP took swabs from my groin, armpits and nostrils which tested positive for Staphylococcus Aureus but negative for PVL. However, the culture grown from the pus from a boil was positive for PVL!
So after a year of treatment for the original Hidradenitis Suppurativa I am in the clear. The MRSA has been eliminated from my system after a decolonisation regime (cleaning and drugs).
My advice is if you have been diagnosed with Hidradenitis Suppurativa rule out MRSA. Get swabs (intra nasal, axilla, groin and definitely from a pus sample produced by a boil) to rule out sensitivities and ask for PVL typing.
Good luck!

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LizH222 said on 15 March 2011

Yes indeed! I agree this should be on the NHS site. Do you get abscesses in your armpits/groin especially - never go away, if they do they soon come back ! Ask your gp to check this condition out. You can also log into the hidradenitis suppuprativa uk organization, just google the word. I suffered for 30 years with this (though my current gp does know about this cdt) - all the doctors & at the hospitals here in north west coast - treated them as boils - they cut them all the time - so painful when they did that, i would pass out, be sick etc and the nurses could never believe the amount that would come out once cut, it left me with permanent and awful scarring in groins and armpits. Do not let anyone cut them like a boil. Most doctors think they are and treat them so. Eventually I when i went to Aberdeen 10 years ago a doctor identified it - sent me to Aberdeen hospital and the operated & cut my armpit out (under anaesthetic ). They could not believe that the hospitals down here actually cut them & said it must have been like ‘torture’! It was. Lots of people seem to have this - yet a lot of gp's & hospitals don't know what it is !
Don't suffer in silence - check out the website.

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marshell said on 24 September 2009

No mention has been made here on a condition known as HIDRADENITIS SUPPURATIVA which I believe to be more common than is thought. This condition results in many abscess and is largely unknown to most Doctors. For anyone suffering from this condition, or anyone who has repeatedly suffered in this way go to www.ba-hs.org.uk/ for more information.

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