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 and the body's immune response 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 nonliving 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.
— Inflammation of tissue due to infection.
— Any of a number of protein chemicals that can change other chemicals.
— Part of the internal female anatomy that carries eggs from the ovaries to the uterus.
— Living inhabitants of a region or area.
— Capable of generating pus. Streptococcus, Staphocococcus
, and bowel bacteria are the primary pyogenic organisms.
— —Tiny structures in the skin that produce oil (sebum). If they become plugged, sebum collects inside and forms a nurturing place for germs to grow.
— The spread of an infectious agent throughout the body by means of the blood stream.
— A tubular channel connecting one body part with another or with the outside.
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 from the 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.
, 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.
Of special note, 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.
Fauci, Anthony S., et al., editors. Harrison's Principles of Internal Medicine. New York: McGraw-Hill, 1997.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.
abscess (ab'ses) [L. abscessus, a going away]
ANTECUBITAL ABSCESS: Antecubital abscess opened to allow drainage of infection
A localized collection of pus in any body part, resulting from invasion of a pyogenic bacterium or other pathogen. Staphylococcus aureus
, e.g., methicillin-resistant S. aureus
(MRSA), is a common cause. The abscess is surrounded by a membrane of variable strength created by macrophages, fibrin, and granulation tissue. Abscesses can disrupt function in adjacent tissues and can be life threatening in some circumstances, e.g., in the lung or within the peritoneal cavity. illustration
An abscess associated with significant inflammation, producing intense heat, redness, swelling, and throbbing pain. The tissue over the abscess becomes elevated, soft, and eventually unstable (fluctuant) and discolored as the abscess comes to a head (points). An abscess can rupture spontaneously or be drained via an incision. If it is left untreated, the pathogens may spread to adjacent tissues or to other parts of the body via the bloodstream. Appearance of or increase in fever may indicate sepsis. illustration
An abscess around the root of a tooth in the alveolar cavity. It is usually the result of necrosis and infection of dental pulp following dental caries. See: periapical abscess
An abscess caused by Entamoeba histolytica. Synonym: endamebic abscess
An abscess in the ischiorectal fossa. It may occur in patients with Crohn disease, diabetes mellitus, or anal fissures more often than in other patients. Incision, drainage, and antibiotics usually provide effective treatment. Synonym: rectal abscess; Synonym: ischiorectal abscess
1. An abscess at the apex of a lung.
2. Periapical abscess.
An abscess around an inflamed or ruptured vermiform appendix.
An abscess or multiple abscesses in the axilla, e.g., in patients with hidradenitis suppurativa.
Bartholin abscess See: Bartholin, Caspar (the younger)
An abscess with two pockets.
bile duct abscess
An abscess of the bile duct. Synonym: cholangitic abscess
An abscess of the gallbladder. It is an infrequent complication of cholangitis or obstruction of the bile duct.
bone abscessBrodie abscess.
An intracranial abscess involving the brain or its membranes. It is seldom primary but usually occurs secondary to infections of the middle ear, nasal sinuses, face, or skull or from contamination from penetrating wounds or skull fractures. It may also have a metastatic origin arising from septic foci in the lungs (bronchiectasis, empyema, lung abscess), in bone (osteomyelitis), or in the heart (endocarditis). Infection of nerve tissue by the invading organism results in necrosis and liquefaction of the tissue, with edema of surrounding tissues. Brain abscesses may be acute, subacute, or chronic. Their clinical manifestations depend on the part of the brain involved, the size of the abscess, the virulence of the infecting organism, and other factors. Synonym: cerebral abscess
; intracranial abscess
Symptoms may include headache, fever, vomiting, malaise, irritability, seizures, or paralysis.
The usual treatment is chemotherapy. Surgical drainage may be required.
breast abscessMammary abscess.
Brodie abscess See: Brodie, Sir Benjamin Collins
An abscess in a bursa.
A breast abscess that discharges into the milk ducts.
An abscess in which the pus has a cheesy appearance.
cerebral abscessBrain abscess.
cholangitic abscessBiliary abscess.
An abscess with pus but without signs of inflammation. It usually develops slowly as a result of liquefaction of tuberculous tissue. It may occur anywhere in or on the body but more frequently in the spine, hips, genitourinary tract, and lymph glands. Symptoms may be very mild. Pain, when present, is caused by pressure on surrounding parts; tenderness is often absent. Chronic septic changes accompanied by afternoon fever may occur. Amyloid disease may develop if the abscess persists for a prolonged period. Synonym: cold abscess
circumtonsillar abscessPeritonsillar abscess.
cold abscessChronic abscess.
Two pus-containing cavities, one larger than the other, connected by a narrow channel.
dentoalveolar abscessPeriapical abscess.
An abscess not circumscribed by a well-defined capsule.
An abscess that disappears without pointing or breaking.
embolic abscessMetastatic abscess.
An abscess containing air or gas, produced by organisms such as Clostridium perfringens. Synonym: gas abscess; tympanitic abscess
endamebic abscessAmebic abscess.
epidural abscessExtradural abscess.
An abscess on the dura mater, an occasional cause of back pain in febrile patients, usually in those who inject drugs. Synonym: epidural abscess
An abscess containing both pus and stool. Synonym: stercoraceous abscess; stercoral abscess
An abscess caused by parasitic infection with microfilariae.
An abscess in a follicle.
An abscess caused by a fungus, e.g., mycetoma. Synonym: mycotic abscess
gas abscessEmphysematous abscess.
An abscess of the gum.
helminthic abscessWorm abscess.
An abscess containing blood.
hepatic abscessLiver abscess.
hot abscessAcute abscess.
hypostatic abscessMetastatic abscess.
An abscess of unknown cause.
An abscess in the iliac region.
An abscess in the psoas and iliacus muscles. It typically results from a local or regional spread of an intestinal or renal abscess or from a blood-borne infection, e.g., after a drug injection. Synonym: psoas abscess
intracranial abscessBrain abscess.
An abscess within the layers of the dura mater.
intraperitoneal abscessPeritoneal abscess.
ischiorectal abscessAnorectal abscess.
An abscess in the kidney, typically following pyelonephritis or a blood-borne infection. The most common causative organisms are gram-negative bacteria from the lower urinary tract that spread to the kidneys and Staphylococcus aureus
from a blood-borne infection. Immunocompromised patients may develop abscesses caused by Nocardia, Candida,
Occasionally, Mycobacterium tuberculosis
are responsible agents. Synonym: renal abscess
Antimicrobial agents are used in combination with surgical drainage. Occasionally, nephrectomy or retroperitoneal exploration is required.
An abscess in a lacrimal gland or in a lacrimal duct.
lateral alveolar abscess
An abscess in periodontal tissue.
liver abscess, abscess of the liver
See: hepatic abscess
An abscess in the liver caused by pathogenic organisms such as those of species of Bacteroides
, or Entamoeba histolytica
The patient will have high fevers; sweats and chills; and an enlarged, painful, tender liver. Pus may be obtained by aspiration.
Embolic (multiple) abscesses are generally fatal. Liver abscesses may heal after they have been evacuated and treated with antibiotics.
An abscess in the lumbar region.
An abscess in lung tissue, caused by anaerobic bacteria such as Staphylococcus aureus or Nocardia species.
An abscess of a lymph node.
An abscess in the female breast, esp. one involving the glandular tissue. It usually occurs during lactation or weaning. Synonym: breast abscess
An abscess of the mastoid portion of the temporal bone.
A secondary abscess at a distance from the focus of infection. Synonym: embolic abscess; hypostatic abscess; wandering abscess
Multiple small embolic abscesses.
A mammary abscess during lactation.
mycotic abscessFungal abscess.
An abscess caused by Nocardia, e.g., in the lung).
An abscess in the orbit of the eye.
An abscess in a maxillary tooth, erupting toward the palate.
An abscess in the tissues of the palm of the hand.
An abscess of pancreatic tissue, usually as a complication of acute pancreatitis or abdominal surgery.
An abscess on the side of the frenulum of the penis.
An abscess between the folds of the broad ligaments of the uterus.
An abscess in the tissues around the kidney. Synonym: perinephric abscess
An abscess in the tissues adjacent to the pancreas. Synonym: peripancreatic abscess
A periodontal abscess arising in the periodontal tissue other than the orifice through which the vascular supply enters the dental pulp.
An abscess of the parotid gland.
An abscess of the pelvic peritoneum, esp. in the pouch of Douglas. It may arise as a complication of a sexually transmitted disease or diverticulitis.
An abscess of the skin around the anus. It usually results from obstruction of intestinal crypts and subsequent fistula formation in the skin. Synonym: periproctic abscess
An abscess at the apex of a tooth, usually resulting from dental caries or tooth trauma. It may be classified further as an acute periapical abscess, a chronic periapical abscess, a periapical granuloma, or a radicular cyst. Synonym: apical abscess
(2); dentoalveolar abscess
An alveolar abscess not involving the apex of a tooth.
An abscess of periodontal tissue.
perinephric abscessParanephric abscess.
An acute or chronic abscess found in the gingiva, periodontal pockets, or periodontal ligament.
peripancreatic abscessParapancreatic abscess.
An abscess in the tissue surrounding the parietal pleura.
periproctic abscessPerianal abscess.
An abscess within the peritoneal cavity usually following peritonitis. It is usually caused by enteric bacteria, e.g., Escherichia coli, enterococci, or Klebsiella. Synonym: intraperitoneal abscess
An abscess of the tissue around the tonsillar capsule. Needle aspiration of the abscess, with subsequent antibiotic therapy, is an effective treatment in 90% of cases. Synonym: circumtonsillar abscess
An abscess in the tissue around a ureter.
An abscess in tissue surrounding the urethra.
An abscess in tissue around the urinary bladder.
An abscess due to infection with pneumococci.
An abscess of the lacrimal sac, producing an inflamed, tender swelling at the inner canthus of the eye.
A subcutaneous or subareolar abscess of the mammary gland.
An abscess within the prostate gland.
An abscess caused by a protozoon.
psoas abscessIliopsoas abscess.
1. An abscess in the pulp chamber of a tooth.
2. An abscess of the tissues of the pulp of a finger.
A metastatic abscess, usually multiple, due to pyogenic organisms.
rectal abscessAnorectal abscess.
renal abscessKidney abscess.
An abscess located behind the cecum. It is an occasional, severe complication of a ruptured appendix or Crohn disease.
An abscess between the mammary gland and the chest wall.
An abscess located between the peritoneum and the posterior abdominal wall. It may arise from an abscess in the kidney or from the spread of an intraperitoneal infection posteriorly.
An abscess of the lymph nodes in the walls of the pharynx. It sometimes simulates diphtheritic pharyngitis.
Staphylococcus aureus and group A hemolytic streptococcus are the most common pathogens.
Typically, a history of pharyngitis is elicited. This is followed by high fever, dysphagia, and refusal to eat. The condition progresses to respiratory distress with hyperextension of the head (“sniffing position”), tachypnea, labored breathing, and drooling. An exquisitely tender bulge in the pharyngeal wall is usually evident.
A retropharyngeal abscess, if fluctuant, should be treated with incision and drainage. If recognized before becoming fluctuant, the abscess should be treated with antibiotics, intravenously administered if the patient is unable to swallow.
An abscess behind the bladder.
A colloquial and veterinary term for periapical abscess.
A colloquial term for a bacterial infection that surrounds a fingernail; a paronychia.
An abscess over the sacrum and coccyx.
An abscess resulting from septicemia.
An abscess of the seminiferous tubules.
An abscess due to necrosis of a vertebra.
An abscess of the spleen. It may arise either from the spread of infection from a neighboring organ (that is, a diverticular abscess or a ruptured gastric ulcer) or from hematogenous spread in patients with infective endocarditis.
stercoraceous abscessFecal abscess
stercoral abscessFecal abscess.
An abscess from which microorganisms cannot be cultivated, an occasional complication of intramuscular injection.
An abscess formed about a stitch or suture.
An abscess caused by streptococci.
An abscess beneath an aponeurosis or fascia.
An abscess of the midlayer of the covering of the brain and spinal cord.
An abscess underneath the areola of the mammary gland, sometimes draining through the nipple.
An abscess beneath the diaphragm, e.g., an hepatic, splenic, or interperitoneal abscess. Synonym: subphrenic abscess
An abscess beneath the dura of the brain or spinal cord.
An abscess beneath the fascia.
An abscess beneath the galea aponeuroticai (the epicranial aponeurosis).
An abscess beneath the pectoral muscles.
A bone abscess below the periosteum.
An abscess between the parietal peritoneum and the abdominal wall.
subphrenic abscessSubdiaphragmatic abscess.
An abscess between the serratus anterior and the posterior thoracic wall.
An abscess beneath the fingernail. It may follow injury from a pin, needle, or splinter.
An abscess of a sweat gland.
An abscess in the suspensory ligament between the liver and the diaphragm.
An abscess occurring in the tertiary stage of syphilis, esp. in bone.
A spinal epidural abscess.
An abscess of the thymus.
Acute suppurative tonsillitis.
tooth abscessAlveolar abscess.
An amebic abscess of the liver.
tuberculous abscessChronic abscess.
An abscess involving both the fallopian tube and the ovary. It is typically transmitted sexually.
tympanitic abscessEmphysematous abscess.
An abscess arising in the tympanum and extending to the neck.
An abscess of both the tympanum and the mastoid.
An abscess in the urethra.
An abscess caused by escape of urine into the tissues.
An abscess that contains pus and urine.
verminous abscessWorm abscess.
wandering abscessMetastatic abscess.
warm abscessAcute abscess.
An abscess caused by or containing insect larvae, worms, or other animal parasites. Synonym: helminthic abscess; verminous abscessillustration
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