Editing Erysipelas (section)

==Diagnosis==
Erysipelas is usually diagnosed by the clinician looking at the characteristic well-demarcated rash following a history of injury or recognition of one of the risk factors.<ref name=Dermnetz/> Tests, if performed, may show a [[neutrophilia|high white-cell count]], raised [[C-reactive protein|CRP]], or positive [[blood culture]] identifying the organism.<ref name=Dermnetz/> Skin cultures are often negative.<ref>{{Cite book |last=Ashton, Leppard |first=Richard, Barbara |title=Differential diagnosis in dermatology |date=9 March 1989 |publisher=Radcliffe Medical Press |isbn=9781870905206 |location=Oxford |pages=44}}</ref>

Erysipelas must be differentiated from [[herpes zoster]], [[angioedema]], [[contact dermatitis]], erythema chronicum migrans of early Lyme disease, gout, septic arthritis, septic bursitis, vasculitis, allergic reaction to an insect bite, acute drug reaction, deep vein thrombosis, and diffuse [[inflammatory breast cancer|inflammatory carcinoma of the breast]].<ref>{{cite journal |url=https://www.ncbi.nlm.nih.gov/books/NBK532247/| title=Erysipelas|website=National Center for Biotechnology Information, U.S. National Library of Medicine | year=2022| pmid=30335280|access-date= 7 July 2021| last1=Michael| first1=Y.| last2=Shaukat| first2=N. M.}}</ref>

===Differentiating from cellulitis===
Erysipelas can be distinguished from cellulitis by two particular features - its raised advancing edge and its sharp borders. The redness in cellulitis is not raised and its border is relatively indistinct.<ref name=Fitzpatrick2009/> Bright redness of erysipelas has been described as a third differentiating feature.<ref name=Stevens2016>{{Citation|last1=Stevens|first1=Dennis L.|title=Impetigo, Erysipelas and Cellulitis|year=2016|url=https://www.ncbi.nlm.nih.gov/books/NBK333408/|work=Streptococcus pyogenes: Basic Biology to Clinical Manifestations|editor-last=Ferretti|editor-first=Joseph J.|publisher=University of Oklahoma Health Sciences Center|pmid=26866211|access-date=8 June 2020|last2=Bryant|first2=Amy E.|editor2-last=Stevens|editor2-first=Dennis L.|editor3-last=Fischetti|editor3-first=Vincent A.}}</ref>

Erysipelas does not affect subcutaneous tissue. It does not release [[pus]], only serum or [[serous fluid]]. Subcutaneous [[edema]] may lead the physician to misdiagnose it as [[cellulitis]].<ref name="UpToDate">{{cite web |last1=Spelman |first1=Denis |title=Cellulitis and skin abscess: Clinical manifestations and diagnosis |url=https://www.uptodate.com/contents/cellulitis-and-skin-abscess-clinical-manifestations-and-diagnosis |website=UpToDate |access-date=30 July 2019 |ref=UpToDate}}</ref>{{clarify|date=June 2020}}