Abscess: Difference between revisions

| image = Five day old Abscess.jpg

| field = [[General surgery]], [[infectious disease (medical specialty)|infectious disease]], [[dermatology]]

An '''abscess''' is a collection of [[pus]] that has built up within the [[tissue (biology)|tissue]] of the body, usually caused by bacterial infection.<ref>{{Cite web |title=Abscess |url=https://my.clevelandclinic.org/health/diseases/22876-abscess |access-date=2025-01-02 |website=[[Cleveland Clinic]] |quote=An abscess is a buildup of a pus that can affect any part of your body.}}</ref><ref>{{Cite web |last=Bush |first=Larry M. |date=Jul 2024 |title=Abscesses |url=https://www.msdmanuals.com/professional/infectious-diseases/biology-of-infectious-disease/abscesses |access-date=2025-01-02 |website=[[MSD Manual]] |quote=Abscesses are collections of pus in confined tissue spaces, usually caused by bacterial infection.}}</ref> Signs and symptoms of abscesses include redness, pain, warmth, and swelling.<ref name=NEJM2014/> The swelling may feel fluid-filled when pressed.<ref name=NEJM2014/> The area of redness often extends beyond the swelling.<ref name=El2009>{{cite book| vauthors = Elston DM |title=Infectious Diseases of the Skin.|date=2009|publisher=Manson Pub. |location=London |isbn=978-1-84076-514-4 |page=12 |url= https://books.google.com/books?id=esPkuOxZajYC&pg=PA12|url-status=live |archive-url=https://web.archive.org/web/20170906120647/https://books.google.com/books?id=esPkuOxZajYC&pg=PA12|archive-date=2017-09-06}}</ref> [[Carbuncle]]s and [[boil]]s are types of abscess that often involve [[hair follicle]]s, with carbuncles being larger.<ref name=Rosen2014Chp120>{{cite book| vauthors = Marx JA |title=Rosen's emergency medicine: concepts and clinical practice|date=2014|publisher=Elsevier/Saunders|location=Philadelphia, PA|isbn=978-1-900151-96-2 |pages=Chapter 120|edition=8th |chapter=Dermatologic Presentations}}</ref> A [[cyst]] is related to an abscess, but it contains a material other than pus, and a cyst has a clearly defined wall. Abscesses can also form internally on internal organs and after surgery.

They are usually caused by a [[bacterial infection]].<ref name=Cox2007>{{cite book| vauthors = Cox C, Turkington JS, Birck D |title=The encyclopedia of skin and skin disorders |date=2007 |publisher=Facts on File|location=New York, NY |isbn=978-0-8160-7509-6 |page=1 |url= https://books.google.com/books?id=GKVPHoIs8uIC&pg=PA1 |edition=3rd|url-status=live|archive-url=https://web.archive.org/web/20170906120647/https://books.google.com/books?id=GKVPHoIs8uIC&pg=PA1|archive-date=2017-09-06}}</ref> Often many different types of bacteria are involved in a single infection.<ref name=El2009/> In many areas of the world, the most common bacteria present are ''[[methicillin-resistant Staphylococcus aureus]]''.<ref name=NEJM2014/> Skin abscesses in particular are overwhelmingly caused by ''S. aureus''.<ref name=":2">{{Cite journal |last1=Johnson |first1=Ryan C. |last2=Ellis |first2=Michael W. |last3=Schlett |first3=Carey D. |last4=Millar |first4=Eugene V. |last5=LaBreck |first5=Patrick T. |last6=Mor |first6=Deepika |last7=Elassal |first7=Emad M. |last8=Lanier |first8=Jeffrey B. |last9=Redden |first9=Cassie L. |last10=Cui |first10=Tianyuan |last11=Teneza-Mora |first11=Nimfa |last12=Bishop |first12=Danett K. |last13=Hall |first13=Eric R. |last14=Bishop-Lilly |first14=Kimberly A. |last15=Merrell |first15=D. Scott |date=2016-10-25 |editor-last=Seleem |editor-first=Mohamed N. |title=Bacterial Etiology and Risk Factors Associated with Cellulitis and Purulent Skin Abscesses in Military Trainees |journal=PLOS ONE |language=en |volume=11 |issue=10 |pages=e0165491 |doi=10.1371/journal.pone.0165491 |doi-access=free |pmid=27780238 |issn=1932-6203 |pmc=5079656|bibcode=2016PLoSO..1165491J }}</ref> Rarely, [[parasites]] can cause abscesses; this is more common in the [[developing world]].<ref name=Rosen2014Chp137/> Diagnosis of a skin abscess is usually made based on what it looks like and is confirmed by cutting it open.<ref name=NEJM2014/> [[Ultrasound]] imaging may be useful in cases in which the diagnosis is not clear.<ref name=NEJM2014/> In abscesses around the [[anus]], [[computer tomography]] (CT) may be important to look for deeper infection.<ref name=Rosen2014Chp137>{{cite book| vauthors = Marx JA |title=Rosen's emergency medicine: concepts and clinical practice|date=2014|publisher=Elsevier/Saunders|location=Philadelphia, PA|isbn=978-1-4557-0605-1 |pages=Chapter 137|edition=8th |chapter=Skin and Soft Tissue Infections}}</ref>

Standard treatment for most skin or soft tissue abscesses is cutting it open and drainage.<ref name="ACEPfive">{{Citation |author1 = American College of Emergency Physicians |author1-link = American College of Emergency Physicians |title = Five Things Physicians and Patients Should Question |publisher = American College of Emergency Physicians |work = [[Choosing Wisely]]: an initiative of the [[ABIM Foundation]] |url = http://www.choosingwisely.org/doctor-patient-lists/american-college-of-emergency-physicians/ |access-date = January 24, 2014 |url-status = live |archive-url = https://web.archive.org/web/20140307012443/http://www.choosingwisely.org/doctor-patient-lists/american-college-of-emergency-physicians/ |archive-date = March 7, 2014 }}</ref> There appears to be some benefit from also using [[antibiotic]]s.<ref>{{cite journal | vauthors = Vermandere M, Aertgeerts B, Agoritsas T, Liu C, Burgers J, Merglen A, Okwen PM, Lytvyn L, Chua S, Vandvik PO, Guyatt GH, Beltran-Arroyave C, Lavergne V, Speeckaert R, Steen FE, Arteaga V, Sender R, McLeod S, Sun X, Wang W, Siemieniuk RA | display-authors = 6 | title = Antibiotics after incision and drainage for uncomplicated skin abscesses: a clinical practice guideline | journal = BMJ | volume = 360 | pages = k243 | date = February 2018 | pmid = 29437651 | pmc = 5799894 | doi = 10.1136/bmj.k243 }}</ref> A small amount of evidence supports not packing the cavity that remains with [[Gauze sponge|gauze]] after drainage.<ref name=NEJM2014>{{cite journal | vauthors = Singer AJ, Talan DA | title = Management of skin abscesses in the era of methicillin-resistant Staphylococcus aureus | journal = The New England Journal of Medicine | volume = 370 | issue = 11 | pages = 1039–1047 | date = March 2014 | pmid = 24620867 | doi = 10.1056/NEJMra1212788 | url = http://enotes.us/SkinAbscess2014.pdf | url-status = dead | access-date = 2014-09-24 | archive-url = https://web.archive.org/web/20141030065311/http://enotes.us/SkinAbscess2014.pdf | archive-date = 2014-10-30 }}</ref> Closing this cavity right after draining it rather than leaving it open may speed healing without increasing the risk of the abscess returning.<ref name=Singer2011>{{cite journal | vauthors = Singer AJ, Thode HC, Chale S, Taira BR, Lee C | title = Primary closure of cutaneous abscesses: a systematic review | journal = The American Journal of Emergency Medicine | volume = 29 | issue = 4 | pages = 361–366 | date = May 2011 | pmid = 20825801 | doi = 10.1016/j.ajem.2009.10.004 | url = http://www.emottawa.ca/assets_secure/journal_club/Sept%2011_2_Singer%202011%20Am%20J%20of%20Emerg%20Med%20Primary%20closure%20of%20cutaneous%20abscesses.pdf | url-status = dead | archive-url = https://web.archive.org/web/20150722040008/http://www.emottawa.ca/assets_secure/journal_club/Sept%2011_2_Singer%202011%20Am%20J%20of%20Emerg%20Med%20Primary%20closure%20of%20cutaneous%20abscesses.pdf | archive-date = 2015-07-22 }}</ref> Sucking out the pus with a needle is often not sufficient.<ref name=NEJM2014/>

Skin abscesses are common and have become more common in recent years.<ref name=NEJM2014/> Risk factors include [[intravenous drug use]], with rates reported as high as 65% among users.<ref name=Langrod2007>{{cite book| vauthors = Ruiz P, Strain EC, Langrod J |title=The substance abuse handbook|date=2007|publisher=Wolters Kluwer Health/Lippincott Williams & Wilkins|location=Philadelphia|isbn=978-0-7817-6045-4 |page=373|url=https://books.google.com/books?id=6LkNShsAw78C&pg=PA373|url-status=live|archive-url=https://web.archive.org/web/20170906120647/https://books.google.com/books?id=6LkNShsAw78C&pg=PA373|archive-date=2017-09-06}}</ref> In 2005, 3.2 million people went to American emergency departments for abscesses.<ref name=Taira2009>{{cite journal | vauthors = Taira BR, Singer AJ, Thode HC, Lee CC | title = National epidemiology of cutaneous abscesses: 1996 to 2005 | journal = The American Journal of Emergency Medicine | volume = 27 | issue = 3 | pages = 289–292 | date = March 2009 | pmid = 19328372 | doi = 10.1016/j.ajem.2008.02.027 }}</ref> In Australia, around 13,000 people were hospitalized in 2008 with the condition.<ref name=Vas2012>{{cite journal | vauthors = Vaska VL, Nimmo GR, Jones M, Grimwood K, Paterson DL | title = Increases in Australian cutaneous abscess hospitalisations: 1999-2008 | journal = European Journal of Clinical Microbiology & Infectious Diseases | volume = 31 | issue = 1 | pages = 93–96 | date = January 2012 | pmid = 21553298 | doi = 10.1007/s10096-011-1281-3 | s2cid = 20376537 }}</ref>

Abscesses may occur in any kind of tissue but most frequently within the skin surface (where they may be superficial pustules known as [[boil]]s or deep skin abscesses), in the [[Lung abscess|lungs]], [[brain abscess|brain]], [[Dental abscess|teeth]], kidneys, and tonsils. Major complications may include spreading of the abscess material to adjacent or remote tissues, and extensive regional tissue death ([[gangrene]]).<ref>{{Cite web |title=Skin abscess: MedlinePlus Medical Encyclopedia |url=https://medlineplus.gov/ency/article/000863.htm |access-date=2023-07-19 |website=medlineplus.gov |language=en}}</ref>

An abscess may form anywhere that bacteria can get through the skin, including insect bites, lacerations, puncture wounds, scrapes, IV injection sites, and other small surface-level injuries. The overwhelming majority of skin abscesses are caused by ''[[Staphylococcus aureus]]'' (methicillin-susceptible or [[Methicillin-resistant Staphylococcus aureus|methicillin-resistant]]) with some studies showing over 90% of documented and cultured skin abscesses being caused by this organism.<ref name=":2" />

Anorectal abscesses can be caused by non-specific obstruction and ensuing infection of the glandular crypts inside of the [[anus]] or [[rectum]]. Other causes include [[cancer]], trauma, or [[inflammatory bowel diseases]].<ref name="h230">{{cite web | last1=Sigmon | first1=David F. | last2=Emmanuel | first2=Bishoy | last3=Tuma | first3=Faiz | title=Perianal Abscess | publisher=StatPearls Publishing | date=2023-06-12 | pmid=29083652 | url=https://www.ncbi.nlm.nih.gov/books/NBK459167/ | access-date=2024-07-28}}</ref>

An ''incisional abscess'' 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.<ref name="Duff2009">{{cite journal| vauthors = Duff P |title=Diagnosis and Management of Postoperative Infection|journal=The Global Library of Women's Medicine|year=2009|issn=1756-2228|doi=10.3843/GLOWM.10032|url=http://www.glowm.com/section_view/heading/Diagnosis%20and%20Management%20of%20Postoperative%20Infection/item/32|url-status=live|archive-url=https://web.archive.org/web/20140714154331/http://www.glowm.com/section_view/heading/Diagnosis%20and%20Management%20of%20Postoperative%20Infection/item/32|archive-date=2014-07-14|url-access=subscription}}</ref> 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]].<ref name="Duff2009"/>

An abscess is a buildup of pus surrounded by normal body tissue. In most cases, abscesses are caused by an infectious species of bacteria, and they function to wall off the infection from uninfected tissues.<ref name=":3" /><ref>{{Cite web |title=abscess |url=https://www.vetneuro.com/index.php/resources/reference/glossary/63-abscess |access-date=2023-07-12 |website=www.vetneuro.com}}</ref><ref name=":0">{{Cite journal |title=A Brief Study on Abscess: A Review |url=https://www.easpublisher.com/journal-details/easjpp/57/434 |journal=EAS Journal of Pharmacy and Pharmacology |volume=3 |issue=5}}</ref>

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.<ref name=":0" />

An abscess is a localized collection of pus (purulent inflammatory tissue) caused by suppuration buried in a tissue, an organ, or a confined space, lined by the pyogenic membrane.<ref>Robins/8th/68</ref> [[Ultrasound]] imaging can help in a diagnosis.<ref>{{cite journal | vauthors = Barbic D, Chenkin J, Cho DD, Jelic T, Scheuermeyer FX | title = In patients presenting to the emergency department with skin and soft tissue infections what is the diagnostic accuracy of point-of-care ultrasonography for the diagnosis of abscess compared to the current standard of care? A systematic review and meta-analysis | journal = BMJ Open | volume = 7 | issue = 1 | pages = e013688 | date = January 2017 | pmid = 28073795 | pmc = 5253602 | doi = 10.1136/bmjopen-2016-013688 }}</ref>

The standard treatment for an uncomplicated skin or soft tissue abscess is the act of opening and draining.<ref name="ACEPfive"/> There does not appear to be any benefit from also using [[antibiotic]]s in most cases.<ref name=NEJM2014/> A small amount of evidence did not find a benefit from packing the abscess with gauze.<ref name=NEJM2014/>

The abscess should be inspected to identify if foreign objects are the cause, which may require their removal. If foreign objects are not the cause, incising and draining the abscess is standard treatment.<ref name="ACEPfive"/><ref>{{cite book |title=Surgery: Facts and Figures | vauthors = Green J, Wajed S |year=2000 |publisher=Cambridge University Press |isbn= 978-1-900151-96-2}}</ref> In most cases, a localized injection of [[Epinephrine; lidocaine hydrochloride|lidocaine and epinephrine]] precedes the incision, to suppress pain.<ref name=":3">Usatine R.P. (2019). Chapter 127: Abscess. Usatine R.P., & Smith M.A., & Mayeaux, Jr. E.J., & Chumley H.S.(Eds.), ''The Color Atlas and Synopsis of Family Medicine, 3e''. McGraw-Hill Education. </ref>

Most people who have an uncomplicated skin abscess should not use antibiotics.<ref name="ACEPfive"/> 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]].<ref name=NEJM2014/> People who are very young or very old may also need antibiotics.<ref name=NEJM2014/> 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.<ref name=NEJM2014/>

In those cases of abscess which do require antibiotic treatment, ''[[Staphylococcus aureus]]'' bacteria are 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|methicillin-resistant ''Staphylococcus aureus'']] (MRSA), and in those cases, traditional antibiotics may be ineffective.<ref name=NEJM2014/> Alternative antibiotics effective against community-acquired MRSA often include [[clindamycin]], [[doxycycline]], [[minocycline]], and [[trimethoprim-sulfamethoxazole]].<ref name=NEJM2014/> 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.<ref name="ACEPfive"/>

Appendiceal abscesses are complications of appendicitis, where there is an infected mass on the appendix. This condition is estimated to occur in 2–10% of appendicitis cases and is usually treated by surgical removal of the appendix (appendicectomy).<ref>{{Cite journal |last1=Cheng |first1=Yao |last2=Xiong |first2=Xianze |last3=Lu |first3=Jiong |last4=Wu |first4=Sijia |last5=Zhou |first5=Rongxing |last6=Cheng |first6=Nansheng |date=2017-06-02 |title=Early versus delayed appendicectomy for appendiceal phlegmon or abscess |journal=The Cochrane Database of Systematic Reviews |volume=2017 |issue=6 |pages=CD011670 |doi=10.1002/14651858.CD011670.pub2 |issn=1469-493X |pmc=6481778 |pmid=28574593}}</ref>

Even without treatment, skin abscesses rarely result in death, as they will naturally break through the skin.<ref name=Rosen2014Chp137/> Other types of abscesses are more dangerous. Brain abscesses may be fatal if untreated. When treated, the mortality rate reduces to 5–10%, but is higher if the abscess ruptures.<ref>{{cite book  | vauthors = Bokhari MR, Mesfin FB | chapter = Brain Abscess|date=2019| chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK441841/ | title = StatPearls|publisher=StatPearls Publishing|pmid=28722871|access-date=2019-07-28}}</ref>