Editing Cellulitis

{{Short description|Bacterial infection of the inner layers of the skin called the dermis}}
{{About|the subcutaneous infection|subcutaneous fat|Cellulite}}
{{cs1 config|name-list-style=vanc}}
{{Infobox medical condition (new)
| name            = Cellulitis 
| image           = Cellulitis3.jpg  
| caption         = Skin cellulitis 
| field = [[Infectious disease (medical specialty)|Infectious disease]], [[dermatology]]
| symptoms        = Red, hot, painful area of skin, [[fever]]<ref name=Vary2014/><ref name=Mint2013/> 
| onset           = 
| duration        = 7–10 days<ref name=Mint2013/> 
| causes          = [[Bacteria]]<ref name=Vary2014/> 
| risks           = Break in the skin, [[obesity]], [[pedal edema|leg swelling]], old age<ref name=Vary2014/> 
| diagnosis       = Based on symptoms<ref name=Vary2014/><ref name=Ed2020>{{cite journal |last1=Edwards |first1=George |last2=Freeman |first2=Karoline |last3=Llewelyn |first3=Martin J. |last4=Hayward |first4=Gail |title=What diagnostic strategies can help differentiate cellulitis from other causes of red legs in primary care? |journal=BMJ |date=12 February 2020 |volume=368 |pages=m54 |doi=10.1136/bmj.m54 |pmid=32051117 |s2cid=211100166 |url=https://figshare.com/articles/journal_contribution/What_diagnostic_strategies_can_help_differentiate_cellulitis_from_other_causes_of_red_legs_in_primary_care/23473595/2/files/41215401.pdf }}</ref>
| differential    = [[Deep vein thrombosis]], [[stasis dermatitis]], [[erysipelas]], [[Lyme disease]], [[necrotizing fasciitis]]. [[Sepsis]] must be ruled out, and if it occurs, must be rapidly treated.<ref name=Vary2014/><ref name=Tint2010/><ref name=IDSALyme2006>{{cite journal |vauthors=Wormser GP, Dattwyler RJ, Shapiro ED, Halperin JJ, Steere AC, Klempner MS, Krause PJ, Bakken JS, Strle F, Stanek G, Bockenstedt L, Fish D, Dumler JS, Nadelman RB |title=The Clinical Assessment, Treatment, and Prevention of Lyme Disease, Human Granulocytic Anaplasmosis, and Babesiosis: Clinical Practice Guidelines by the Infectious Diseases Society of America |journal=Clinical Infectious Diseases |volume=43 |issue=9 |pages=1089–1134 |date=1 November 2006 |doi=10.1086/508667 |pmid=17029130 |doi-access=free}}</ref>
| treatment       = Elevation of the affected area<ref name=Tint2010/> 
| medication      = Antibiotics such as [[cephalexin]]<ref name=Vary2014/><ref name=BMJ2012/>  
| frequency       = 21.2 million (2015)<ref name=GBD2015Pre/> 
| deaths          = 16,900 (2015)<ref name=GBD2015De/> 
}}
<!-- Definition and symptoms -->
'''Cellulitis''' is usually<ref name="Bansal Nimmatoori Singhania et al 2020">{{cite journal |last1=Bansal |first1=Saurabh |last2=Nimmatoori |first2=Divya P. |last3=Singhania |first3=Namrata |last4=Lin |first4=Rone Chun |last5=Nukala |first5=Chandra Mouli |last6=Singh |first6=Anil K. |last7=Singhania |first7=Girish |title=Severe nonbacterial preseptal cellulitis from adenovirus detected via pooled meta-genomic testing |journal=Clinical Case Reports |date=3 November 2020 |volume=8 |issue=12 |pages=3503–3506 |doi=10.1002/ccr3.3468 |pmid=33363960 |pmc=7752574 }}</ref> a bacterial infection involving the inner layers of the [[skin]].<ref name=Vary2014/> It specifically affects the [[dermis]] and [[subcutaneous fat]].<ref name=Vary2014/> Signs and symptoms include an area of redness which increases in size over a few days.<ref name=Vary2014/> The borders of the area of redness are generally not sharp and the skin may be swollen.<ref name=Vary2014/> While the redness often turns white when pressure is applied, this is not always the case.<ref name=Vary2014/> The area of infection is usually painful.<ref name=Vary2014/> [[Lymphatic vessels]] may occasionally be involved,<ref name=Vary2014/><ref name=Tint2010>{{cite book |author=Tintinalli, Judith E. |title=Emergency Medicine: A Comprehensive Study Guide (Emergency Medicine (Tintinalli)) |publisher=McGraw-Hill Companies |location=New York |year=2010 |pages=1016 |edition=7th |isbn=978-0-07-148480-0}}</ref> and the person may have a [[fever]] and feel tired.<ref name=Mint2013>{{cite journal |last=Mistry |first=RD |title=Skin and soft tissue infections |journal=Pediatric Clinics of North America |date=Oct 2013 |volume=60 |issue=5 |pages=1063–82 |pmid=24093896 |doi=10.1016/j.pcl.2013.06.011}}</ref>

<!-- Cause and diagnosis -->
The legs and face are the most common sites involved, although cellulitis can occur on any part of the body.<ref name=Vary2014/> The leg is typically affected following a break in the skin.<ref name=Vary2014/> Other [[risk factor]]s include [[obesity]], [[pedal edema|leg swelling]], and old age.<ref name=Vary2014/> For facial infections, a break in the skin beforehand is not usually the case.<ref name=Vary2014/> The bacteria most commonly involved are [[streptococci]] and ''[[Staphylococcus aureus]]''.<ref name=Vary2014/> In contrast to cellulitis, [[erysipelas]] is a bacterial infection involving the more superficial layers of the skin, present with an area of redness with well-defined edges, and more often is associated with a fever.<ref name=Vary2014/> The diagnosis is usually based on the presenting signs and symptoms, while a [[cell culture]] is rarely possible.<ref name=Vary2014>{{cite journal |last=Vary |first=JC |author2=O'Connor, KM |title=Common Dermatologic Conditions |journal=Medical Clinics of North America |date=May 2014 |volume=98 |issue=3 |pages=445–85 |pmid=24758956 |doi=10.1016/j.mcna.2014.01.005}}</ref><ref name=Ed2020/> Before making a diagnosis, more serious infections such as an underlying [[osteomyelitis|bone infection]] or [[necrotizing fasciitis]] should be ruled out.<ref name=Tint2010/>

<!-- Diagnosis and treatment -->
Treatment is typically with [[antibiotic]]s taken by mouth, such as [[cephalexin]], [[amoxicillin]] or [[cloxacillin]].<ref name=Vary2014/><ref name=BMJ2012/> Those who are allergic to [[penicillin]] may be prescribed [[erythromycin]] or [[clindamycin]] instead.<ref name=BMJ2012/> When [[methicillin-resistant Staphylococcus aureus|methicillin-resistant ''S. aureus'']] (MRSA) is a concern, [[doxycycline]] or [[trimethoprim/sulfamethoxazole]] may, in addition, be recommended.<ref name=Vary2014/> There is concern related to the presence of [[pus]] or previous MRSA infections.<ref name=Vary2014/><ref name=Mint2013/> Elevating the infected area may be useful, as may [[analgesics|pain killers]].<ref name=Tint2010/><ref name=BMJ2012/>

<!-- Prognosis and epidemiology -->
Potential complications include [[abscess]] formation.<ref name=Vary2014/> Around 95% of people are better after 7 to 10 days of treatment.<ref name=Mint2013/> Those with diabetes, however, often have worse outcomes.<ref name=Dryden2015>{{cite journal |last=Dryden |first=M |title=Pathophysiology and burden of infection in patients with diabetes mellitus and peripheral vascular disease: focus on skin and soft-tissue infections |journal=Clinical Microbiology and Infection |date=Sep 2015 |volume=21 |pages=S27–S32 |doi=10.1016/j.cmi.2015.03.024 |pmid=26198368 |doi-access=free}}</ref> Cellulitis occurred in about 21.2 million people in 2015.<ref name=GBD2015Pre>{{cite journal |vauthors = ((GBD 2015 Disease and Injury Incidence and Prevalence Collaborators))|title=Global, regional, and national incidence, prevalence, and years lived with disability for 310 diseases and injuries, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015 |journal=Lancet |date=8 October 2016 |volume=388 |issue=10053 |pages=1545–1602 |pmid=27733282 |pmc=5055577 |doi=10.1016/S0140-6736(16)31678-6}}</ref> In the United States about 2 of every 1,000 people per year have a case affecting the lower leg.<ref name=Vary2014/> Cellulitis in 2015 resulted in about 16,900 deaths worldwide.<ref name=GBD2015De>{{cite journal |vauthors=((GBD 2015 Mortality and Causes of Death Collaborators)) |title=Global, regional, and national life expectancy, all-cause mortality, and cause-specific mortality for 249 causes of death, 1980-2015: a systematic analysis for the Global Burden of Disease Study 2015 |journal=Lancet |date=8 October 2016 |volume=388 |issue=10053 |pages=1459–1544 |pmid=27733281 |pmc=5388903 |doi=10.1016/S0140-6736(16)31012-1}}</ref> In the United Kingdom, cellulitis was the reason for 1.6% of admissions to a hospital.<ref name=BMJ2012>{{cite journal |last=Phoenix |first=G |author2=Das, S |author3=Joshi, M |s2cid=28902459 |title=Diagnosis and management of cellulitis |journal=BMJ |series=Clinical Research |date=Aug 7, 2012 |volume=345 |pages=e4955 |pmid=22872711 |doi=10.1136/bmj.e4955}}</ref>

==Signs and symptoms==
The typical signs and symptoms of cellulitis are an area that is red, hot, and painful. The photos shown here are of mild to moderate cases and are not representative of the earlier stages of the condition.{{citation needed|date=May 2021}}

<gallery widths="200" heights="200">
File:CellulitisJmh649.JPG|Cellulitis following an abrasion: Note the red streaking up the arm from the involvement of the lymphatic system.
File:Cellulitis1.jpg|Infected left shin in comparison to the right-sided shin with no sign of symptoms.
File:Cellulitis Of The Leg.jpg|Cellulitis of the leg with foot involvement.
</gallery>

===Complications===
Potential complications may include [[abscess]] formation, [[fasciitis]], and [[sepsis]].<ref name=Vary2014/><ref>{{cite book |title=Rook's textbook of dermatology |date=2016 |publisher=Wiley-Blackwell |isbn=978-1-118-44119-0 |page=26.18 |edition=9}}</ref>

==Causes==

Cellulitis is usually, but not always,<ref name="Bansal Nimmatoori Singhania et al 2020"/> caused by [[bacterium|bacteria]] that enter and infect the tissue through breaks in the skin. [[Group A streptococcal infection|Group A]] ''[[Streptococcus]]'' and ''[[Staphylococcus]]'' are the most common causes of the infection and may be found on the skin as normal biota in healthy individuals.<ref>{{cite web |url=https://www.lecturio.com/concepts/cellulitis/ |title=Cellulitis |website=The Lecturio Medical Concept Library |access-date=7 July 2021 |archive-date=20 August 2021 |archive-url=https://web.archive.org/web/20210820030214/https://www.lecturio.com/concepts/cellulitis/ |url-status=live }}</ref>

About 80% of cases of [[Ludwig's angina]], or cellulitis of the submandibular space, are caused by dental infections. Mixed infections, due to both aerobes and anaerobes, are commonly associated with this type of cellulitis. Typically, this includes [[streptococcus#Alpha-hemolytic|alpha-hemolytic streptococci]], staphylococci, and [[bacteroides|bacteroides']] groups.<ref name="Dhingra">{{cite book |last1=Dhingra |first1=PL |last2=Dhingra |first2=Shruti |editor1-last= Nasim |editor1-first= Shabina |others=Dhingra, Deeksha |title=Diseases of Ear, Nose and Throat |edition=5th |year=2010 |orig-year= 1992 |publisher=Elsevier |location=New Delhi |isbn=978-81-312-2364-2 |pages=277–78}}</ref>

Predisposing conditions for cellulitis include an insect or [[spider bite]], [[blister]]ing, an animal bite, [[tattoos]], [[Itch|pruritic]] (itchy) skin rash, recent [[surgery]], [[athlete's foot]], [[xeroderma|dry skin]], [[eczema]], injecting drugs (especially subcutaneous or intramuscular injection or where an attempted intravenous injection "misses" or blows the vein), pregnancy, diabetes, and obesity, which can affect circulation, as well as burns and [[boil]]s, although debate exists as to whether minor foot lesions contribute. Occurrences of cellulitis may also be associated with the rare condition [[hidradenitis suppurativa]] or dissecting cellulitis.<ref name="Cellulitis: All You Need to Know">{{cite web |url=https://www.cdc.gov/groupastrep/diseases-public/Cellulitis.html |title=Cellulitis: All You Need to Know |website=National Center for Immunization and Respiratory Diseases, Division of Bacterial Diseases (CDC) |date=4 February 2021 |access-date=7 July 2021 |archive-date=8 July 2021 |archive-url=https://web.archive.org/web/20210708161812/https://www.cdc.gov/groupastrep/diseases-public/cellulitis.html |url-status=live }}</ref>

The appearance of the skin assists a doctor in determining a diagnosis. A doctor may also suggest blood tests, a wound culture, or other tests to help rule out a blood clot deep in the veins of the legs. Cellulitis in the lower leg is characterized by signs and symptoms similar to those of a [[deep vein thrombosis]], such as warmth, pain, and swelling (inflammation).

Reddened skin or rash may signal a deeper, more serious infection of the inner layers of skin. Once below the skin, the bacteria can spread rapidly, entering the lymph nodes and the bloodstream and spreading throughout the body. This can result in influenza-like symptoms with a high temperature and sweating or feeling very cold with shaking, as the affected person cannot get warm.<ref name="Cellulitis: All You Need to Know"/>

In rare cases, the infection can spread to the deep layer of tissue called the [[fascial]] lining. [[Necrotizing fasciitis]], also called by the media "flesh-eating bacteria", is an example of a deep-layer infection. It is a [[medical emergency]].<ref>{{cite web |title=Necrotizing Fasciitis: A Rare Disease, Especially for the Healthy |url=https://www.cdc.gov/Features/NecrotizingFasciitis/ |website=CDC |access-date=7 July 2021 |date=June 15, 2016 |url-status=live |archive-url=https://web.archive.org/web/20160809193909/http://www.cdc.gov/features/necrotizingfasciitis/ |archive-date=9 August 2016}}</ref>

===Risk factors===
{{more citations needed | section | date=June 2021}}
The elderly and those with [[immunodeficiency|a weakened immune system]] are especially vulnerable to contracting cellulitis. {{citation needed|date=June 2021}} [[diabetes mellitus|Diabetics]] are more susceptible to cellulitis than the general population because of impairment of the immune system; they are especially prone to cellulitis in the feet, because the disease causes impairment of blood circulation in the legs, leading to diabetic foot or foot ulcers. Poor control of blood glucose levels allows bacteria to grow more rapidly in the affected tissue and facilitates rapid progression if the infection enters the bloodstream. Neural degeneration in diabetes means these ulcers may not be painful, thus often become infected. Those who have had [[poliomyelitis]] are also prone because of circulatory problems, especially in the legs.{{citation needed|date=March 2017}}

Immunosuppressive drugs, and other illnesses or infections that weaken the immune system, are also factors that make infection more likely. [[Chickenpox]] and [[shingles]] often result in blisters that break open, providing a gap in the skin through which bacteria can enter. [[Lymphedema]], which causes swelling on the arms and/or legs, can also put an individual at risk.{{citation needed|date=May 2021}}
Diseases that affect blood circulation in the legs and feet, such as [[chronic venous insufficiency]] and [[varicose veins]], are also risk factors for cellulitis.{{citation needed|date=June 2021}}

Cellulitis is also common among dense populations sharing hygiene facilities and common living quarters, such as military installations, college dormitories, nursing homes, oil platforms, and homeless shelters.{{citation needed|date=June 2021}}

==Diagnosis==
Cellulitis is most often a clinical diagnosis, readily identified in many people by history and physical examination alone, with rapidly spreading areas of cutaneous [[edema|swelling]], redness, and heat, occasionally associated with inflammation of regional lymph nodes. While classically distinguished as a separate entity from erysipelas by spreading more deeply to involve the subcutaneous tissues, many clinicians may classify erysipelas as cellulitis.  Both are often treated similarly, but cellulitis associated with [[Boil|furuncles]], [[carbuncle]]s, or [[abscess]]es is usually caused by ''[[Staphylococcus aureus|S. aureus]]'', which may affect treatment decisions, especially antibiotic selection.<ref name=":0">{{cite journal |last1=Stevens |first1=Dennis L. |last2=Bisno |first2=Alan L. |last3=Chambers |first3=Henry F. |last4=Dellinger |first4=E. Patchen |last5=Goldstein |first5=Ellie J. C. |last6=Gorbach |first6=Sherwood L. |last7=Hirschmann |first7=Jan V. |last8=Kaplan |first8=Sheldon L. |last9=Montoya |first9=Jose G. |last10=Wade |first10=James C. |title=Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the infectious diseases society of America |journal=Clinical Infectious Diseases|date=15 July 2014 |volume=59 |issue=2 |pages=147–159 |doi=10.1093/cid/ciu296 |pmid=24947530 |doi-access= }}</ref> Skin aspiration of nonpurulent cellulitis, usually caused by streptococcal organisms, is rarely helpful for diagnosis, and [[blood culture]]s are positive in fewer than 5% of all cases.<ref name=":0" />

It is important to evaluate for co-existent abscess, as this finding usually requires surgical drainage as opposed to antibiotic therapy alone.  Physicians' clinical assessment for abscess may be limited, especially in cases with extensive overlying induration, but use of [[Medical ultrasound|bedside ultrasonography]] performed by an experienced practitioner readily discriminates between abscess and cellulitis and may change management in up to 56% of cases.<ref name=":1">{{cite journal |last1=Singer |first1=Adam J. |last2=Talan |first2=David A. |title=Management of skin abscesses in the era of methicillin-resistant Staphylococcus aureus |journal=The New England Journal of Medicine |date=13 March 2014 |volume=370 |issue=11 |pages=1039–1047 |doi=10.1056/NEJMra1212788 |pmid=24620867 }}</ref> Use of ultrasound for abscess identification may also be indicated in cases of antibiotic failure.  Cellulitis has a characteristic "cobblestoned" appearance indicative of subcutaneous edema without a defined hypoechoic, heterogeneous fluid collection that would indicate abscess.<ref>{{cite book |last1=Mayeaux |first1=E. J. |title=The Essential Guide to Primary Care Procedures |date=2015 |publisher=Lippincott Williams & Wilkins |isbn=978-1-4963-1871-8 }}{{page needed|date=November 2022}}</ref>

===Differential diagnosis===
Other conditions that may mimic cellulitis include [[Venous thrombosis|deep vein thrombosis]], which can be diagnosed with a compression leg [[medical ultrasonography|ultrasound]], and [[stasis dermatitis]], which is inflammation of the skin from poor blood flow. Signs of a more severe infection such as necrotizing fasciitis or [[gas gangrene]] that would require prompt surgical intervention include purple [[bulla (dermatology)|bulla]]e, skin sloughing, subcutaneous edema, and systemic toxicity.<ref name=":0" /> Misdiagnosis can occur in up to 30% of people with suspected lower-extremity cellulitis, leading to 50,000 to 130,000 unnecessary hospitalizations and $195 to $515 million in avoidable healthcare spending annually in the United States.<ref>{{Cite journal |last1=Weng |first1=Qing Yu |last2=Raff |first2=Adam B. |last3=Cohen |first3=Jeffrey M. |last4=Gunasekera |first4=Nicole |last5=Okhovat |first5=Jean-Phillip |last6=Vedak |first6=Priyanka |last7=Joyce |first7=Cara |last8=Kroshinsky |first8=Daniela |last9=Mostaghimi |first9=Arash |title=Costs and Consequences Associated With Misdiagnosed Lower Extremity Cellulitis |journal=JAMA Dermatology |volume=153 |issue=2 |pages=141–146 |doi=10.1001/jamadermatol.2016.3816 |pmid=27806170 |year=2017 |s2cid=205110504 |url=https://dash.harvard.edu/bitstream/1/33785925/1/jamadermatology_Weng_2016_oi_160057.pdf }}</ref> Evaluation by dermatologists for cases of suspected cellulitis has been shown to reduce misdiagnosis rates and improve patient outcomes.<ref name="pmid29453874">{{cite journal |vauthors = Li DG, Xia FD, Khosravi H, Dewan AK, Pallin DJ, Baugh CW | display-authors=etal |title=Outcomes of Early Dermatology Consultation for Inpatients Diagnosed With Cellulitis. |journal=JAMA Dermatol |year=2018 |volume=154 |issue=5 |pages=537–543 |pmid=29453874 |doi=10.1001/jamadermatol.2017.6197 |pmc=5876861}}</ref><ref name="pmid29453872">{{cite journal |vauthors = Ko LN, Garza-Mayers AC, St John J, Strazzula L, Vedak P, Shah R | display-authors=etal |title=Effect of Dermatology Consultation on Outcomes for Patients With Presumed Cellulitis: A Randomized Clinical Trial. |journal=JAMA Dermatol |year=2018 |volume=154 |issue=5 |pages=529–536 |pmid=29453872 |doi=10.1001/jamadermatol.2017.6196 |pmc=5876891}}</ref>

Associated musculoskeletal findings are sometimes reported. When it occurs with [[acne conglobata]], [[hidradenitis suppurativa]], and [[pilonidal cyst]]s, the syndrome is referred to as the [[follicular occlusion triad]] or tetrad.<ref>{{cite journal |vauthors=Scheinfeld NS |title=A case of dissecting cellulitis and a review of the literature |journal=Dermatology Online Journal |volume=9 |issue=1 |pages=8 |date=February 2003 |doi=10.5070/D39D26366C |pmid=12639466 }}</ref>

[[Lyme disease]] can be misdiagnosed as cellulitis. The characteristic [[Erythema chronicum migrans|bullseye rash]] does not always appear in Lyme disease (the rash may not have a central or ring-like clearing, or not appear at all).<ref name=wright_2012>{{cite journal |last1=Wright |first1=William F. |last2=Riedel |first2=David J. |last3=Talwani |first3=Rohit |last4=Gilliam |first4=Bruce L. |title=Diagnosis and management of Lyme disease |journal=American Family Physician |date=1 June 2012 |volume=85 |issue=11 |pages=1086–1093 |pmid=22962880 |url=https://www.aafp.org/link_out?pmid=22962880 }}</ref> Factors supportive of Lyme include recent outdoor activities where Lyme is common and rash at an unusual site for cellulitis, such as [[armpit]], [[groin]], or behind the knee.<ref name=CDC-Lyme-Data>{{cite web |title=Lyme Disease Data and surveillance |url=https://www.cdc.gov/lyme/datasurveillance/ |website=Lyme Disease |publisher=Centers for Disease Control and Prevention |access-date=April 12, 2019 |date=2019-02-05 |archive-date=2019-04-13 |archive-url=https://web.archive.org/web/20190413133319/https://www.cdc.gov/lyme/datasurveillance/ |url-status=live }}</ref><ref name=wright_2012/> Lyme can also result in long-term neurologic complications.<ref name=Aucott2015>{{cite journal |vauthors=Aucott JN |title=Posttreatment Lyme disease syndrome |journal=Infectious Disease Clinics of North America |volume=29 |issue=2 |pages=309–323 |date=June 2015 |pmid=25999226 |doi=10.1016/j.idc.2015.02.012}}</ref> The standard treatment for cellulitis, [[cephalexin]], is not useful in Lyme disease.<ref name=IDSALyme2006/> When it is unclear which one is present, the [[Infectious Diseases Society of America|IDSA]] recommends treatment with [[cefuroxime axetil]] or [[amoxicillin/clavulanic acid]], as these are effective against both infections.<ref name=IDSALyme2006/>

==Prevention==
In those who have previously had cellulitis, the use of antibiotics may help prevent future episodes.<ref>{{cite journal |last=Oh |first=CC |author2=Ko, HC |author3=Lee, HY |author4=Safdar, N |author5=Maki, DG |author6=Chlebicki, MP |title=Antibiotic prophylaxis for preventing recurrent cellulitis: A systematic review and meta-analysis |journal=Journal of Infection |date=Feb 24, 2014 |pmid=24576824 |doi=10.1016/j.jinf.2014.02.011 |volume=69 |issue=1 |pages=26–34}}</ref> This is recommended by [[Clinical Resource Efficiency Support Team]] (CREST) for those who have had more than two episodes.<ref name=BMJ2012/><ref>{{Cite journal|title=Accuracy of CREST Guideline in Management of Cellulitis in Emergency Department; a Systematic Review and Meta-analysis|first1=Hossein|last1=Akhavan|first2=Seyed Reza|last2=Habibzadeh|first3=Fatemeh|last3=Maleki|first4=Mahdi|last4=Foroughian|first5=Sayyed Reza|last5=Ahmadi|first6=Reza|last6=Akhavan|first7=Bita|last7=Abbasi|first8=Behzad|last8=Shahi|first9=Navid|last9=Kalani|first10=Naser|last10=Hatami|first11=Amir|last11=Mangouri|first12=Sheida|last12=Jamalnia|date=2021-11-03|journal=Archives of Academic Emergency Medicine|volume=9|issue=1|pages=e69|doi=10.22037/aaem.v9i1.1422|pmid=34870235|pmc=8628644}}</ref> A 2017 meta-analysis found a benefit of preventative antibiotics for recurrent cellulitis in the lower limbs, but the preventative effects appear to diminish after stopping antibiotic therapy.<ref>{{cite journal |last1=Dalal |first1=Adam |last2=Eskin-Schwartz |first2=Marina |last3=Mimouni |first3=Daniel |last4=Ray |first4=Sujoy |last5=Days |first5=Walford |last6=Hodak |first6=Emmilia |last7=Leibovici |first7=Leonard |last8=Paul |first8=Mical |title=Interventions for the prevention of recurrent erysipelas and cellulitis |journal=The Cochrane Database of Systematic Reviews |date=June 2017 |volume=2017 |issue=6 |pages=CD009758 |doi=10.1002/14651858.CD009758.pub2 |pmid=28631307 |pmc=6481501 }}</ref>

==Treatment==
Antibiotics are usually prescribed, with the agent selected based on suspected organism and presence or absence of [[purulence]],<ref name=":0" /> although the best treatment choice is unclear.<ref>{{cite journal |last1=Kilburn |first1=SA |last2=Featherstone |first2=P |last3=Higgins |first3=B |last4=Brindle |first4=R |title=Interventions for cellulitis and erysipelas |journal=The Cochrane Database of Systematic Reviews |date=16 June 2010 |volume=2020 |issue=6 |pages=CD004299 |pmid=20556757 |doi=10.1002/14651858.CD004299.pub2|pmc=8693180 }}</ref>  If an abscess is also present, surgical drainage is usually indicated, with antibiotics often prescribed for co-existent cellulitis, especially if extensive.<ref name=":1" />  Pain relief is also often prescribed, but excessive pain should always be investigated, as it is a symptom of [[necrotizing fasciitis]].  Elevation of the affected area is often recommended.<ref name="pmid32965485">{{cite journal |vauthors = Han J, Faletsky A, Mostaghimi A |title=Cellulitis. |journal=JAMA Dermatol |year=2020 |volume=156 |issue=12 |page=1384 |pmid=32965485 |doi=10.1001/jamadermatol.2020.2083 | doi-access=|s2cid=221862981 }}</ref>

[[Steroids]] may speed recovery in those on antibiotics.<ref name=Vary2014/>

===Antibiotics===
Antibiotics choices depend on regional availability, but a penicillinase-resistant [[semisynthetic penicillin]] or a first-generation [[cephalosporin]] is currently recommended for cellulitis without abscess.<ref name=":0" /> A course of antibiotics is not effective in between 6 and 37% of cases.<ref>{{cite journal |last1=Obaitan |first1=Itegbemie |last2=Dwyer |first2=Richard |last3=Lipworth |first3=Adam D. |last4=Kupper |first4=Thomas S. |last5=Camargo |first5=Carlos A. |last6=Hooper |first6=David C. |last7=Murphy |first7=George F. |last8=Pallin |first8=Daniel J. |title=Failure of antibiotics in cellulitis trials: a systematic review and meta-analysis |journal=The American Journal of Emergency Medicine |date=May 2016 |doi=10.1016/j.ajem.2016.05.064 |pmid=27344098 |volume=34 |issue=8 |pages=1645–52}}</ref>

==Epidemiology==
Cellulitis in 2015 resulted in about 16,900 deaths worldwide, up from 12,600 in 2005.<ref name=GBD2015De/>

Cellulitis is a common global health burden, with more than 650,000 admissions per year in the United States alone. In the United States, an estimated 14.5 million cases annually of cellulitis account for $3.7 billion in ambulatory care costs alone. The majority of cases of cellulitis are nonculturable and therefore the causative bacteria are unknown. In the 15% of cellulitis cases in which organisms are identified, most are due to β-hemolytic [[Streptococcus]] and [[Staphylococcus aureus]].<ref>{{cite journal |last1=Raff |first1=Adam B. |last2=Kroshinsky |first2=Daniela |title=Cellulitis: A Review |journal=JAMA |date=19 July 2016 |volume=316 |issue=3 |pages=325–337 |doi=10.1001/jama.2016.8825 |pmid=27434444 |s2cid=241077983 }}</ref>

==Other animals==
[[Horse]]s may acquire cellulitis, usually secondarily to a wound (which can be extremely small and superficial) or to a deep-tissue infection, such as an abscess or infected bone, tendon sheath or joint.<ref name="pmid16882479">{{cite journal |vauthors=Adam EN, Southwood LL |title=Surgical and traumatic wound infections, cellulitis, and myositis in horses |journal=Veterinary Clinics of North America: Equine Practice |volume=22 |issue=2 |pages=335–61, viii |date=August 2006 |pmid=16882479 |doi=10.1016/j.cveq.2006.04.003 }}</ref><ref name="pmid18296664">{{cite journal |vauthors=Fjordbakk CT, Arroyo LG, Hewson J |title=Retrospective study of the clinical features of limb cellulitis in 63 horses |journal=Veterinary Record |volume=162 |issue=8 |pages=233–36 |date=February 2008 |pmid=18296664 |doi=10.1136/vr.162.8.233 |s2cid=18579931 }}</ref> Cellulitis from a superficial wound usually creates less [[lameness (equine)|lameness]] (grade 1–2 of 5) than that caused by septic arthritis (grade 4–5). The horse exhibits inflammatory edema, which is hot, painful swelling. This swelling differs from [[filled legs|stocking up]] in that the horse does not display symmetrical swelling in two or four legs, but in only one leg. This swelling begins near the source of infection, but eventually continues down the leg. In some cases, the swelling also travels distally. Treatment includes cleaning the wound and caring for it properly, the administration of [[NSAID]]s, such as [[phenylbutazone]], cold hosing, applying a sweat wrap or a [[poultice]], and mild exercise.{{citation needed|date=June 2020}}

==See also==
* [[Haemophilus influenzae cellulitis|''Haemophilus influenzae'' cellulitis]]
* [[Helicobacter cellulitis|''Helicobacter'' cellulitis]]
* [[Tuberculous cellulitis]]

==References==
{{Reflist}}

==Further reading==
*{{cite journal |last1=Stevens |first1=DL |last2=Bisno |first2=AL |last3=Chambers |first3=HF |last4=Dellinger |first4=EP |last5=Goldstein |first5=EJ |last6=Gorbach |first6=SL |last7=Hirschmann |first7=JV |last8=Kaplan |first8=SL |last9=Montoya |first9=JG|last10=Wade|first10=JC |title=Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the infectious diseases society of America. |journal=Clinical Infectious Diseases |date=15 July 2014 |volume=59 |issue=2 |pages=147–59 |pmid=24947530 |doi=10.1093/cid/ciu296 |doi-access=}}

==External links==
* {{cite web |url=https://webnetstudy.com/cellulitis-cellulite-symptoms-causes-treatment/html |publisher=U.S. National Library of Medicine |work=MedlinePlus |title=Cellulitis|date=24 December 2023 }}

{{Medical condition classification and resources|
| DiseasesDB     = 29806
| ICD10          = {{ICD10|L|03||l|00}}
| ICD9           = {{ICD9|682.9}}
| ICDO           =
| OMIM           =
| MedlinePlus    = 000855
| eMedicineSubj  = med
| eMedicineTopic = 310
| eMedicine_mult = {{eMedicine2|emerg|88}} {{eMedicine2|derm|464}}
| MeshID         = D00248
}}

{{Diseases of the skin and appendages by morphology}}
{{Bacterial cutaneous infections}}

[[Category:Bacterium-related cutaneous conditions]]
[[Category:Disorders of fascia]]
[[Category:Equine injury and lameness]]
[[Category:Inflammations]]
[[Category:Wikipedia medicine articles ready to translate]]
[[Category:Wikipedia emergency medicine articles ready to translate]]