An abscess is a cavity containing pus and surrounded by inflamed tissue, formed as a result of a localized infection.
An abscess may develop, enlarge or subside, depending on whether microorganisms or leukocytes (white blood cells) gain the upper hand in any one of a number of locations in the body. Abscesses may develop in any organ and in the soft tissues beneath the skin in any area.
Common sites include the breast, gums and peri-rectal area. Rarer sites include the liver and the brain. Common sites for abscesses under the skin include the axilla (armpit) and the groin. These two areas have a large number of lymph glands that are responsible for fighting infection.
A collar-button abscess is one in which a small abscess cavity under the skin connects via a sinus to (channel) to a much larger one in deeper tissues.
Abscesses can be caused by minor breaks and punctures of the skin, obstruction of sweat glands and oil (sebaceous) glands, and inflammation of hair follicles. They contain dead cells, bacteria, and other debris, which causes inflammation and pain. Common bacteria, such as staphylococci, are the most common cause, although the bacillus responsible for tuberculosis is an important abscess-forming type.
Fungal infections sometimes cause abscesses, while amoebae (single-celled protozoal parasites) are an important cause of liver abscesses.
The infection usually reaches an organ via the bloodstream or penetrates tissues under the skin via an infected wound or bite.
People with weakened immune systems may be more prone to abscesses or may have more severe ones.
Abscesses tend to get worse as time goes on. Symptoms include tenderness or pain and the site of the abscess being warm to the touch. Symptoms of discomfort or pain depend mainly on the site of the abscess, though larger ones - since they are a source of infection within the body – can cause fever, chills, sweating, and malaise.
Abscesses close to the skin usually cause inflammation with redness, increased skin temperature and tenderness.
Tuberculous abscesses are the exception; hence their introduction as cold abscesses.
Call your doctor if you have a high fever, or if the abscess is larger than ½ inch across, is near your rectal area or groin, or if red streaks are radiating out from the abscess.
An abscess is diagnosed clinically by means of the history and a physical exam, demonstrating a tender mass with overlying erythema (redness).
Small abscesses may be helped by applying warm compresses to the area several times a day. This will sometimes promote spontaneous drainage of the abscess which is important since the primary treatment of abscesses is to drain them. However, it is also important to not attempt to drain an abscess yourself. This can lead to trauma of the surrounding tissue and potentially help spread the underlying infection.
Draining the abscess is done by making a cut in the lining and providing an escape route for the pus, either through a drainage tube or by leaving the cavity open to the skin. The area around the abscess will be numbed before draining. Most people feel immediately better after the draining.
Many abscesses subside after drainage alone; others subside after drainage and drug treatment. Occasionally, their presence within a vital organ, such as the liver or brain, damages enough surrounding tissue to cause some permanent loss of normal function.
Antibiotics are usually prescribed to treat a bacterial infection, antifungal drugs to treat fungi, and antiamebic drugs to treat amebiasis. However, the lining of the abscess cavity tends to reduce the amount of drug that can penetrate the source of infection from the bloodstream.
Without spontaneous or surgical drainage, sometimes an abscess will be reabsorbed into the bloodstream. Incomplete reabsorbtion leaves a cystic loculation (small pouches) within a fibrous wall where calcium salts sometimes accumulate to form a calcified mass.