View source for Boil

{{Short description|Medical condition (infection)}}
{{About|the contagious skin disease|the change in state from liquid to gas|Boiling|other uses}}
{{Use dmy dates|date=October 2020}}
{{Infobox medical condition
| name            = Boils
| synonyms        =
| image           = Furoncle.jpg
| caption         = Furuncle
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| field           = {{hlist|[[Dermatology]]|[[general surgery]]}}
| symptoms        = {{hlist|Painful|small|rough skin growth}}
| complications   =
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| causes          = {{hlist|[[Bacteria]]|[[ingrown hair]]}}
| risks           =
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A '''boil''', also called a '''furuncle''', is a deep [[folliculitis]], which is an [[infection]] of the [[hair follicle]]. It is most commonly caused by infection by the [[bacterium]] ''[[Staphylococcus aureus]]'', resulting in a painful swollen area on the [[skin]] caused by an accumulation of [[pus]] and dead tissue.<ref name=medline>{{MedlinePlusEncyclopedia|001474|Furuncle}}</ref> Boils are therefore basically pus-filled nodules.<ref>{{cite web|url = http://www.healthguidance.org/entry/11040/1/Causes-and-Cures-of-Skin-Boils.html|title= Causes and Cures of Skin |author=<!--Staff writer(s); no by-line.--> |website= Healthguidance.org |access-date= 26 July 2014}}</ref> Individual boils clustered together are called [[carbuncle]]s.<ref name=medline2>{{MedlinePlusEncyclopedia|000825|Carbuncle}}</ref>
Most human infections are caused by coagulase-positive ''S. aureus'' [[Strain (biology)|strains]], notable for the bacteria's ability to produce [[coagulase]], an [[enzyme]] that can clot blood. Almost any [[organ system]] can be infected by ''S. aureus''.

==Signs and symptoms==
[[File:Riehl Zumbusch Tafel III (2).jpg|thumb|Close-up of boil showing sloughing and necrosis]]
Boils are bumpy, red, [[pus]]-filled lumps around a hair follicle that are [[Tenderness (medicine)|tender]], warm, and painful.  They range from pea-sized to golf ball-sized. A yellow or white point at the center of the lump can be seen when the boil is ready to drain or discharge pus. In a severe infection, an individual may experience [[fever]], swollen [[lymph node]]s, and [[fatigue (medical)|fatigue]]. A recurring boil is called chronic furunculosis.<ref name=medline/><ref name=Bolognia>{{cite book |vauthors=Blume JE, Levine EG, Heymann WR |chapter=Bacterial diseases |veditors=Bolognia JL, Jorizzo JL, Rapini RP |title=Dermatology |publisher=Mosby |year=2003 |isbn=0-323-02409-2 |page=1126 }}</ref><ref name=habif>{{cite book |author=Habif, TP |chapter=Furuncles and carbuncles |title=Clinical Dermatology: A Color Guide to Diagnosis and Therapy |publisher=Mosby |location=Philadelphia PA |year=2004 |edition=4th }}</ref><ref name=wolf>{{cite book |author=Wolf K |chapter=Section 22. Bacterial infections involving the skin |title=Fitzpatrick's Color Atlas & Synopsis of Clinical Dermatology |publisher=McGraw-Hill |year=2005 |edition=5th |display-authors=etal}}</ref> Skin infections tend to be recurrent in many patients and often spread to other family members. Systemic factors that lower resistance commonly are detectable, including: [[diabetes]], [[obesity]], and [[hematologic disorder]]s.<ref>{{cite journal |vauthors=Steele RW, Laner SA, Graves MH |title=Recurrent staphylococcal infection in families |journal=Arch Dermatol |volume=116 |issue=2 |pages=189–90 |date=February 1980 |pmid=7356349|doi= 10.1001/archderm.1980.01640260065016|url=http://repub.eur.nl/pub/7628 |hdl=1765/7628 |hdl-access=free }}</ref>

Boils may appear on the buttocks or near the anus, the back, the neck, the belly, the chest, the arms or legs, or even in the ear canal.<ref>{{cite web|url = http://patient.info/health/boils-carbuncles-and-furunculosis|title = Boils, Carbuncles and Furunculosis|author = <!--Staff writer(s); no by-line.-->|website = Patient.info|access-date = 26 July 2014}}</ref> Boils may also appear around the eye, where they are called [[stye]]s.<ref>{{cite web|url = http://www.kidshealth.org.nz/boils|title= Boils, Kidshealth |author=<!--Staff writer(s); no by-line.--> |date= 13 September 2011 |access-date= 26 July 2014}}</ref>

===Complications===
The most common [[complication (medicine)|complication]]s of boils are [[scarring]] and [[infection]] or [[abscess]] of the [[skin]], [[spinal cord]], [[brain]], [[kidney]]s, or other organs. Infections may also spread to the bloodstream ([[bacteremia]]) and become life-threatening.<ref name=habif/><ref name=wolf/>  ''S. aureus'' strains first infect the skin and its structures (for example, [[sebaceous gland]]s, [[hair follicle]]s) or invade damaged skin (cuts, abrasions). Sometimes the infections are relatively limited (such as a [[stye]], boil, furuncle, or carbuncle), but other times they may spread to other skin areas (causing [[cellulitis]], [[folliculitis]], or [[impetigo]]). Unfortunately, these bacteria can reach the bloodstream ([[bacteremia]]) and end up in many different body sites, causing infections (wound infections, abscesses, [[osteomyelitis]], [[endocarditis]], [[pneumonia]])<ref>{{cite journal |vauthors=Lina G, Piémont Y, Godail-Gamot F, Bes M, Peter MO, Gauduchon V, Vandenesch F, Etienne J |title=Involvement of Panton-Valentine leukocidin-producing ''Staphylococcus aureus'' in primary skin infections and pneumonia |journal=Clin Infect Dis |volume=29 |issue=5 |pages=1128–32 |date=November 1999 |pmid=10524952 |doi=10.1086/313461|doi-access=free }}</ref> that may severely harm or kill the infected person. ''S. aureus'' strains also produce [[enzymes]] and [[exotoxins]] that likely cause or increase the severity of certain diseases. Such diseases include [[food poisoning]], [[septic shock]], [[toxic shock syndrome]], and [[Staphylococcal scalded skin syndrome|scalded skin syndrome]].<ref>{{cite web|url=http://www.emedicinehealth.com/staphylococcus/page4_em.htm|title=Staph Infection Causes, Symptoms, Treatment – Staph Infection Diagnosis|work=eMedicineHealth}}</ref>

==Causes==

===Bacteria===
Naturally the cause is bacteria such as [[staphylococci]] that are present on the skin. Bacterial colonisation begins in the [[hair follicle]]s and can cause local [[cellulitis]] and inflammation.<ref name=medline/><ref name=habif/><ref name=wolf/> [[Myiasis]] caused by the [[Cordylobia anthropophaga|tumbu fly]] in Africa usually presents with cutaneous furuncles.<ref>{{cite journal |vauthors=Tamir J, Haik J, Schwartz E |title=Myiasis with Lund's fly (''Cordylobia rodhaini'') in travellers |journal=J Travel Med |volume=10 |issue=5 |pages=293–95 |year=2003 |pmid=14531984 |doi=10.2310/7060.2003.2732|doi-access=free }}</ref> [[Risk factor]]s for furunculosis include [[bacteria]]l carriage in the nostrils, [[diabetes mellitus]], [[obesity]], [[Lymphoproliferative disorders|lymphoproliferative]] [[neoplasm]]s, [[malnutrition]], and use of [[immunosuppressive drug]]s.<ref>{{cite journal |author=Scheinfeld NS |title=Furunculosis |journal=Consultant |volume=47 |issue=2 |year=2007 |url=http://www.consultantlive.com/display/article/10162/36304 |access-date=31 August 2009 |archive-date=23 November 2012 |archive-url=https://web.archive.org/web/20121123092305/http://www.consultantlive.com/display/article/10162/36304 |url-status=dead }}</ref>

===Family history===
People with recurrent boils are as well more likely to have a positive family history, take antibiotics, and to have been hospitalised, [[anemic]], or diabetic; they are also more likely to have associated skin diseases and multiple lesions.<ref name=ElGilany09>{{cite journal |vauthors=El-Gilany AH, Fathy H |title=Risk factors of recurrent furunculosis |journal=Dermatol Online J |volume=15 |issue=1 |pages=16 |date=January 2009 |doi=10.5070/D39NG6M0BN |pmid=19281721 |url=http://dermatology.cdlib.org/1501/letters/furunculosis/elgilany.html|url-access=subscription }}</ref>

===Other===
Other causes include [[Immunodeficiency|poor immune system function]] such as from [[HIV/AIDS]], [[diabetes]], [[malnutrition]], or [[alcoholism]].<ref name=Demo2012/> Poor hygiene and [[obesity]] have also been linked.<ref name=Demo2012>{{cite journal|last1=Demos|first1=M|last2=McLeod|first2=MP|last3=Nouri|first3=K|title=Recurrent furunculosis: a review of the literature.|journal=The British Journal of Dermatology|date=Oct 2012|volume=167|issue=4|pages=725–32|pmid=22803835|doi=10.1111/j.1365-2133.2012.11151.x|s2cid=25415894}}</ref> It may occur following antibiotic use due to the development of resistance to the antibiotics used.<ref name=Laube02>{{cite journal |vauthors=Laube S, Farrell M |title=Bacterial skin infection in the elderly: diagnosis and treatment |journal=Drugs & Aging |volume=19 |issue=5 |pages=331–42 |year=2002 |pmid=12093320 |doi=10.2165/00002512-200219050-00002 |s2cid=24264303 }}</ref> An associated skin disease favors recurrence. This may be attributed to the persistent colonization of abnormal skin with ''S. aureus'' strains, such as is the case in persons with [[atopic dermatitis]].<ref name=Laube02/>
Boils which recur under the arm, breast or in the groin area may be associated with [[hidradenitis suppurativa]] (HS).<ref>{{cite web|url=http://www.hstrust.org/info|title=What is this boil like abscess under your arm, breast or groin|work=The Hidradenitis Suppurativa Trust|access-date=28 September 2015|archive-url=https://web.archive.org/web/20150929010339/http://www.hstrust.org/info|archive-date=29 September 2015|url-status=dead}}</ref>

==Diagnosis==
Diagnosis is made through clinical evaluation by a physician, which may include culturing of the lesion.<ref name=Merck>{{cite news |url= https://www.merckmanuals.com/professional/dermatologic-disorders/bacterial-skin-infections/furuncles-and-carbuncles|title= Furuncles and Carbuncles|newspaper= Merck Manuals Professional Edition|date = August 2017| access-date= 29 April 2018}}</ref> Evaluation can further include imaging, such as an ultrasound, to evaluate for formation of an abscess or other complications.

==Treatment==
A boil may clear up on its own without bursting, but more often it will need to be opened and drained. This will usually happen spontaneously within two weeks. Regular application of a [[warm moist compress]], both before and after a boil opens, can help speed healing. The area must be kept clean, hands washed after touching it, and any dressings disposed of carefully, in order to avoid spreading the bacteria. A doctor may cut open or "[[Incision and drainage|lance]]" a boil to allow it to drain, but squeezing or cutting should not be attempted at home, as this may further spread the infection. [[Antibiotic]] therapy may be recommended for large or recurrent boils or those that occur in sensitive areas (such as the groin, breasts, armpits, around or in the nostrils, or in the ear).<ref name=medline/><ref name=Bolognia/><ref name=habif/><ref name=wolf/> An antibiotic should not be used for longer than one month, with at least two months (preferably longer) between uses, otherwise it will lose its effectiveness.<ref>[http://www.mayoclinic.com/health/boils-and-carbuncles/DS00466/DSECTION=symptoms Mayo Clinic]  {{webarchive|url=https://web.archive.org/web/20120815234857/http://www.mayoclinic.com/health/boils-and-carbuncles/DS00466/DSECTION%3Dsymptoms |date=15 August 2012  }}</ref>

Furuncles at risk of leading to serious complications should be incised and drained if antibiotics or steroid injections are not effective. These include furuncles that are unusually large, last longer than two weeks, or occur in the middle of the face or near the spine.<ref name=medline/><ref name=wolf/> Fever and chills are signs of [[sepsis]] and indicate immediate treatment.<ref>{{cite web |url=http://www.mayoclinic.com/health/boils-and-carbuncles/DS00466/DSECTION=complications |title=Boils and carbuncles: Complications - MayoClinic.com |access-date=2012-08-14 |url-status=dead |archive-url=https://web.archive.org/web/20120815144700/http://www.mayoclinic.com/health/boils-and-carbuncles/DS00466/DSECTION%3Dcomplications |archive-date=15 August 2012}}</ref>

''Staphylococcus aureus'' has the ability to acquire [[antimicrobial resistance]] easily, making treatment difficult. Knowledge of the antimicrobial resistance of ''S. aureus'' is important in the selection of antimicrobials for treatment.<ref>{{cite journal |vauthors=Nagaraju U, Bhat G, Kuruvila M, Pai GS, Babu RP |title=Methicillin-resistant ''Staphylococcus aureus'' in community-acquired pyoderma |journal=Int J Dermatol |volume=43 |issue=6 |pages=412–14 |year=2004 |pmid=15186220 |doi=10.1111/j.1365-4632.2004.02138.x |s2cid=38742158 }}</ref>

==See also==
* [[Cutaneous condition]]
* [[Nodule (medicine)]]

==References==
{{Reflist}}

== External links ==
{{Commons category|Furuncles}}
* {{DermAtlas|1817374494}}

{{Medical resources
| DiseasesDB      = 29434
| ICD10           = {{ICD10|L|02||l|00}}
| ICD9            = {{ICD9|680.9}}
| ICDO            =
| OMIM            =
| MedlinePlus     = 001474
| eMedicineSubj   =
| eMedicineTopic  =
| MeshID          = D005667
| SNOMED CT       = 416675009
}}
{{Diseases of the skin and appendages by morphology}}
{{Bacterial cutaneous infections}}
{{Authority control}}

[[Category:Bacterium-related cutaneous conditions]]