An abscess is a collection of pus caused by infection by microorganisms, usually bacteria. Pus is formed from destroyed tissue cells, from leukocytes (a type of white blood cell) that have been carried to the area to fight infection, and from dead and live microorganisms. A lining, known as a pyogenic membrane, often forms around the abscess.
Types of abscess
An abscess may develop in any organ, and in the soft tissues beneath the skin, sometimes as a collar-stud abscess, a small cavity that connects to a larger cavity in deeper tissues. Common sites of abscesses include the armpit, breast groin, and gums. Rarer sites include the liver and brain.
Cause and incidence
Common bacteria, such as staphylococci, are the usual cause of abscesses, although fungal infections are another cause. Amoebae (single-celled microorganisms) are an important cause of liver abscesses. Infectious organisms reach internal organs via the bloodstream or penetrate to tissues under the skin through an infected wound or bite. People with impaired immunity, such as those who are taking immunosuppressant drugs and those with HIV infection or AIDS, are especially susceptible to abscesses.
An abscess may cause pain, depending on where it occurs. Most larger abscesses cause fever (sometimes with chills), sweating, and malaise. Abscesses may produce a sensation of intense pressure and those close to the skin may cause redness and swelling.
Antibiotic drugs are usually prescribed to treat bacterial infections, antifungal drugs are used to treat fungal infections, and amoebicides are used for amoebiasis. Most abscesses need to be drained by making a cut in the lining of the abscess cavity to allow the pus to escape; a tube may be left in place to allow continuous drainage. Some abscesses burst and drain spontaneously.
Many abscesses subside following drainage alone; others subside after a combination of drainage and drug treatment. Occasionally the presence of an abscess within a vital organ damages enough surrounding tissue to cause permanent loss of normal function, or even death.
Abscess in more detail - non - technical
An abscess is an enclosed collection of liquefied tissue, known as pus, somewhere in the body. It is the result of the body’s defensive reaction to foreign material
There are two types of abscesses, septic and sterile. Most abscesses are septic, which means that they are the result of an infection. Septic abscesses can occur anywhere in the body. Only a germ (bacteria) and the body’s immuneresponse are required. In response to the invading germ, white blood cells gather at the infected site and begin producing chemicals called enzymes that attack the germ by digesting it. These enzymes act like acid, killing the germs and breaking them down into small pieces that can be picked up by the circulation and eliminated from the body. Unfortunately, these chemicals also digest body tissues. In most cases, the germ produces similar chemicals. The result is a thick, yellow liquid–pus–containing digested germs, digested tissue, white blood cells, and enzymes.
An abscess is the last stage of a tissue infection that begins with a process called inflammation. Initially, as the invading germ activates the body’s immune system, several events occur:
- Blood flow to the area increases
- The temperature of the area increases due to the increased blood supply
- The area swells due to the accumulation of water, blood, and other liquids
- It turns red
- It hurts, because of the irritation from the swelling and the chemical activity
These four signs—heat, swelling, redness, and pain—characterize inflammation
As the process progresses, the tissue begins to turn to liquid, and an abscess forms. It is the nature of an abscess to spread as the chemical digestion liquefies more and more tissue. Furthermore, the spreading follows the path of least resistance—the tissues most easily digested. A good example is an abscess just beneath the skin. It most easily continues along beneath the skin rather than working its way through the skin where it could drain its toxic contents. The contents of the abscess also leak into the general circulation and produce symptoms just like any other infection. These include chills, fever, aching, and general discomfort.
Sterile abscesses are sometimes a milder form of the same process caused not by germs but by non-living irritants such as drugs. If an injected drug like penicillin is not absorbed, it stays where it was injected and may cause enough irritation to generate a sterile abscess– sterile because there is no infection involved. Sterile abscesses are quite likely to turn into hard, solid lumps as they scar, rather than remaining pockets of pus.
Causes and symptoms
Many different agents cause abscesses. The most common are the pus-forming (pyogenic) bacteria like Staphylococcus aureus, which is nearly always the cause of abscesses under the skin. Abscesses near the large bowel, particularly around the anus, may be caused by any of the numerous bacteria found within the large bowel. Brain abscesses and liver abscesses can be caused by any organism that can travel there through the circulation. Bacteria, amoeba, and certain fungi can travel in this fashion. Abscesses in other parts of the body are caused by organisms that normally inhabit nearby structures or that infect them. Some common causes of specific abscesses are:
- skin abscesses by normal skin flora
- dental and throat abscesses by mouth flora
- lung abscesses by normal airway flora, pneumonia germs, or tuberculosis
- abdominal and anal abscesses by normal bowel flora
Specific types of abscesses
Listed below are some of the more common and important abscesses.
Carbuncles and other boils. Skin oil glands (sebaceous glands) on the back or the back of the neck are the ones usually infected. The most common germ involved is Staphylococcus aureus. Acne is a similar condition of sebaceous glands on the face and back.
Pilonidal abscess. Many people have as a birth defect a tiny opening in the skin just above the anus. Fecal bacteria can enter this opening, causing an infection and subsequent abscess.
Retropharyngeal, parapharyngeal, peritonsillar abscess. As a result of throat infections like strep throat and tonsillitis, bacteria can invade the deeper tissues of the throat and cause an abscess. These abscesses can compromise swallowing and even breathing. Lung abscess. During or after pneumonia, whether it’s due to bacteria [common pneumonia], tuberculosis, fungi, parasites, or other germs, abscesses can develop as a complication.
Liver abscess. Bacteria or amoeba from the intestines can spread through the blood to the liver and cause abscesses.
Psoas abscess. Deep in the back of the abdomen on either side of the lumbar spine lie the psoas muscles. They flex the hips. An abscess can develop in one of these muscles, usually when it spreads from the appendix, the large bowel, or the fallopian tubes.
The common findings of inflammation—heat, redness, swelling, and pain—easily identify superficial abscesses. Abscesses in other places may produce only generalized symptoms such as fever and discomfort. If the patient’s symptoms and physical examination do not help, a physician may have to resort to a battery of tests to locate the site of an abscess, but usually something in the initial evaluation directs the search. Recent or chronic disease in an organ suggests it may be the site of an abscess. Dysfunction of an organ or system—for instance, seizures or altered bowel function—may provide the clue. Pain and tenderness on physical examination are common findings. Sometimes a deep abscess will eat a small channel (sinus) to the surface and begin leaking pus. A sterile abscess may cause only a painful lump deep in the buttock where a shot was given.
Since skin is very resistant to the spread of infection, it acts as a barrier, often keeping the toxic chemicals of an abscess from escaping the body on their own. Thus, the pus must be drained fromthe abscess by a physician. The surgeon determines when the abscess is ready for drainage and opens a path to the outside, allowing the pus to escape. Ordinarily, the body handles the remaining infection, sometimes with the help of antibiotics or other drugs. The surgeon may leave a drain (a piece of cloth or rubber) in the abscess cavity to prevent it from closing before all the pus has drained out.
If an abscess is directly beneath the skin, it will be slowly working its way through the skin as it is more rapidly working its way elsewhere. Since chemicals work faster at higher temperatures, applications of hot compresses to the skin over the abscess will hasten the digestion of the skin and eventually result in its breaking down, releasing the pus spontaneously. This treatment is best reserved for smaller abscesses in relatively less dangerous areas of the body—limbs, trunk, back of the neck. It is also useful for all superficial abscesses in their very early stages. It will ‘‘ripen’’ them.
Contrast hydrotherapy, alternating hot and cold compresses, can also help assist the body in resorption of the abscess. There are two homeopathic remedies that work to rebalance the body in relation to abscess formation, Silica and Hepar sulphuris. In cases of septic abscesses, bentonite clay packs (bentonite clay and a small amount of Hydrastis powder) can be used to draw the infection from the area.
Once the abscess is properly drained, the prognosis is excellent for the condition itself. The reason for the abscess (other diseases the patient has) will determine the overall outcome. If, on the other hand, the abscess ruptures into neighboring areas or permits the infectious agent to spill into the bloodstream, serious or fatal consequences are likely. Abscesses in and around the nasal sinuses, face, ears, and scalp may work their way into the brain. Abscesses within an abdominal organ such as the liver may rupture into the abdominal cavity. In either case, the result is life threatening. Blood poisoning is a term commonly used to describe an infection that has spilled into the blood stream and spread throughout the body from a localized origin. Blood poisoning, known to physicians as septicemia, is also life threatening.
Abscesses in the hand are more serious than they might appear. Due to the intricate structure and the overriding importance of the hand, any hand infection must be treated promptly and competently.
Infections that are treated early with heat (if superficial) or antibiotics will often resolve without the formation of an abscess. It is even better to avoid infections altogether by taking prompt care of open injuries, particularly puncture wounds. Bites are the most dangerous of all, even more so because they often occur on the hand.