A boil is a common example of an abscess in the skin, but abscesses can occur in almost any part of the body. Abscesses inside the body usually occur in the spaces between the internal organs.
Pus is mainly a collection of millions of dead cells from your immune system that have tried to deal with an infection. Pus also contains many germs and the dead body cells
Symptoms often depend on whereabouts in the body the abscess occurs. There is often pain in the affected area and a general feeling of illness, with fever, sweats, chills and general aches and pains.
A skin abscess may appear as an open wound or sore, or as a smooth lump under the skin. The area may be warm and tender to touch. People with white or pale skin may notice that the skin around the area is reddened.
The usual cause of an abscess is an infection with bacteria. Certain bacteria are more likely to be pus-forming as they make toxins (chemicals) which can damage the body's tissues. These include: Staphylococcus aureus and Streptococcus pyogenes.
Abscesses occur for several reasons. For example, skin abscesses may occur when the oil (sebaceous) glands or sweat glands become blocked, the hair follicles become inflamed (this is called a perifollicular abscess), or from minor wounds to the skin.
Germs get under the skin or into these glands, and are fought off by the body's defences.
People with weakened immune systems are more likely to develop abscesses. These include people with AIDS, cancer, or diabetes, people who are having treatment such as chemotherapy or chronic steroid therapy, and those who have had serious trauma such as extensive burns.
Skin abscesses can often be diagnosed by a physical examination of the area. Your doctor will probably ask you for your medical history to help him or her find the cause of the problem. They may also ask you how long the abscess has been there, if you have been injured in that area, whether you have had any fever or illness and if you are taking any medications.
An abscess on an internal organ may be diagnosed by X-ray or scanning. Sometimes an operation is needed to detect it.
See your doctor if you have an abscess, because it may need to be drained of pus to stop the infection spreading. This is particularly important if you have another condition such as diabetes, cancer or AIDS, or if your temperature goes over 38.3ºC (101 F).
You may need a small operation to open the abscess and let the pus drain out.
Sometimes an abscess forms its own drainage track to the surface. This is called a sinus and tends to be permanent unless both the abscess and the track are removed surgically.
Antibiotics are only effective if the abscess wall is broken down. This is because they cannot penetrate the abscess wall to fight the infection inside.
A more complicated operation is needed to drain an abscess from inside the body. The techniques vary, depending on where the abscess is in the body.
You can help to prevent skin abscesses by washing your skin at least once a day with water and soap. Take care when shaving your face, legs, underarms or pubic area to avoid nicking your skin.