This article is about the medical condition. For the death metal band, see Abscess (band).
|Other names||Latin: Abscessus|
|Five-day-old inflamed epidermal inclusion cyst. The black spot is a keratin plug which connects with the underlying cyst.|
|Specialty||General surgery, Infectious disease, dermatology|
|Symptoms||Redness, pain, swelling|
|Causes||Bacteria (often MRSA)|
|Risk factors||Intravenous drug use|
|Diagnostic method||Ultrasound, CT scan|
|Differential diagnosis||Cellulitis, sebaceous cyst, necrotising fasciitis|
|Treatment||Cutting it open|
|Frequency||~1% per year (United States)|
An abscess is a collection of pus that has built up within the tissue of the body. Signs and symptoms of abscesses include redness, pain, warmth, and swelling. The swelling may feel fluid-filled when pressed. The area of redness often extends beyond the swelling. Carbuncles and boils are types of abscess that often involve hair follicles, with carbuncles being larger.
They are usually caused by a bacterial infection. Often many different types of bacteria are involved in a single infection. In the United States and many other areas of the world the most common bacteria present is methicillin-resistant Staphylococcus aureus. Rarely, parasites can cause abscesses; this is more common in the developing world. Diagnosis of a skin abscess is usually made based on what it looks like and is confirmed by cutting it open. Ultrasound imaging may be useful in cases in which the diagnosis is not clear. In abscesses around the anus, computer tomography (CT) may be important to look for deeper infection.
Standard treatment for most skin or soft tissue abscesses is cutting it open and drainage. There appears to be some benefit from also using antibiotics. A small amount of evidence supports not packing the cavity that remains with gauze after drainage. Closing this cavity right after draining it rather than leaving it open may speed healing without increasing the risk of the abscess returning. Sucking out the pus with a needle is often not sufficient.
Skin abscesses are common and have become more common in recent years. Risk factors include intravenous drug use, with rates reported as high as 65% among users. In 2005 in the United States, 3.2 million people went to the emergency department for an abscess. In Australia, around 13,000 people were hospitalized in 2008 with the condition.
Abscesses may occur in any kind of tissue but most frequently on skin surface (where they may be superficial pustules (boils) or deep skin abscesses), in the lungs, brain, teeth, kidneys, and tonsils. Major complications are spreading of the abscess material to adjacent or remote tissues, and extensive regional tissue death (gangrene).
An internal abscess is more difficult to identify, but signs include pain in the affected area, a high temperature, and generally feeling unwell. Internal abscesses rarely heal themselves, so prompt medical attention is indicated if such an abscess is suspected. An abscess can potentially be fatal depending on where it is located.
Abscesses are caused by bacterial infection, parasites, or foreign substances. Bacterial infection is the most common cause. Often many different types of bacteria are involved in a single infection. In the United States and many other areas of the world the most common bacteria present is methicillin-resistant Staphylococcus aureus. Among spinal subdural abscesses, methicillin-sensitive Staphylococcus aureus is the most common organism involved.
See also: Anorectal abscess
Perianal abscesses can be seen in patients with for example inflammatory bowel disease (such as Crohn's disease) or diabetes. Often the abscess will start as an internal wound caused by ulceration, hard stool or penetrative objects with insufficient lubrication. This wound typically becomes infected as a result of the normal presence of feces in the rectal area, and then develops into an abscess. This often presents itself as a lump of tissue near the anus which grows larger and more painful with time. Like other abscesses, perianal abscesses may require prompt medical treatment, such as an incision and debridement or lancing.
An incisional abscess is one that develops as a complication secondary to a surgical incision. It presents as redness and warmth at the margins of the incision with purulent drainage from it. If the diagnosis is uncertain, the wound should be aspirated with a needle, with aspiration of pus confirming the diagnosis and availing for Gram stain and bacterial culture.
An abscess is a defensive reaction of the tissue to prevent the spread of infectious materials to other parts of the body.
The final structure of the abscess is an abscess wall, or capsule, that is formed by the adjacent healthy cells in an attempt to keep the pus from infecting neighboring structures. However, such encapsulation tends to prevent immune cells from attacking bacteria in the pus, or from reaching the causative organism or foreign object.
Abscesses should be differentiated from empyemas, which are accumulations of pus in a preexisting rather than a newly formed anatomical cavity.
See also: Incision and drainage
In critical areas where surgery presents a high risk, it may be delayed or used as a last resort. The drainage of a lung abscess may be performed by positioning the patient in a way that enables the contents to be discharged via the respiratory tract. Warm compresses and elevation of the limb may be beneficial for a skin abscess.
Most people who have an uncomplicated skin abscess should not use antibiotics. Antibiotics in addition to standard incision and drainage is recommended in persons with severe abscesses, many sites of infection, rapid disease progression, the presence of cellulitis, symptoms indicating bacterial illness throughout the body, or a health condition causing immunosuppression. People who are very young or very old may also need antibiotics. If the abscess does not heal only with incision and drainage, or if the abscess is in a place that is difficult to drain such as the face, hands, or genitals, then antibiotics may be indicated.
In those cases of abscess which do require antibiotic treatment, Staphylococcus aureus bacteria is a common cause and an anti-staphylococcus antibiotic such as flucloxacillin or dicloxacillin is used. The Infectious Diseases Society of America advises that the draining of an abscess is not enough to address community-acquired methicillin-resistant Staphylococcus aureus (MRSA), and in those cases, traditional antibiotics may be ineffective. Alternative antibiotics effective against community-acquired MRSA often include clindamycin, doxycycline, minocycline, and trimethoprim-sulfamethoxazole. The American College of Emergency Physicians advises that typical cases of abscess from MRSA get no benefit from having antibiotic treatment in addition to the standard treatment. If the condition is thought to be cellulitis rather than abscess, consideration should be given to possibility of strep species as cause that are still sensitive to traditional anti-staphylococcus agents such as dicloxacillin or cephalexin in patients able to tolerate penicillin. Antibiotic therapy alone without surgical drainage of the abscess is seldom effective due to antibiotics often being unable to get into the abscess and their ineffectiveness at low pH levels.
In North America, after drainage, an abscess cavity is often packed, perhaps with cloth, in an attempt to protect the healing wound. However, evidence from emergency medicine literature reports that packing wounds after draining causes pain to the person and does not decrease the rate of recurrence, nor bring faster healing or fewer physician visits.
More recently, several North American hospitals have opted for less-invasive loop drainage over standard drainage and wound packing. In one study of 143 pediatric outcomes, a failure rate of 1.4% was reported in the loop group versus 10.5% in the packing group (P<.030), while a separate study reported a 5.5% failure rate among loop patients.
Skin abscesses are common and have become more common in recent years. Risk factors include intravenous drug use, with rates reported as high as 65% among users. In 2005 in the United States 3.2 million people went to the emergency department for an abscess. In Australia around 13,000 people were hospitalized in 2008 for the disease.
An abscess is so called because there is an abscessus (a going away or departure) of portions of the animal tissue from each other to make room for the suppurated matter lodged between them.
The following types of abscess are listed in the medical dictionary:
|Look up abscess in Wiktionary, the free dictionary.|
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