Editing Cellulitis (section)

{{Short description|Bacterial infection of the inner layers of the skin called the dermis}}
{{About|the subcutaneous infection|subcutaneous fat|Cellulite}}
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{{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>