Last reviewed: 30 Oct 2021
Last updated: 11 Oct 2021

Summary

Definition

History and exam

Key diagnostic factors

  • presence of risk factors
  • anaesthesia or severe pain over site of infection
  • fever
  • palpitations, tachycardia, tachypnoea, hypotension, and lightheadedness
  • nausea and vomiting
  • delirium
  • crepitus
  • vesicles or bullae
  • grey discoloration of skin
  • oedema or induration
  • location of lesion

Risk factors

  • inpatient contact with index case
  • Varicella zoster infection
  • cutaneous injury, surgery, trauma
  • non-traumatic skin lesions
  • intravenous drug use
  • chronic illness
  • immunosuppression
  • non-steroidal anti-inflammatory drugs (NSAIDs)

Diagnostic investigations

1st investigations to order

  • surgical exploration
  • blood and tissue cultures
  • Gram stain
  • full blood count and differential
  • serum electrolytes
  • serum urea and creatinine
  • serum CRP
  • serum creatine kinase
  • liver function tests
  • clotting screen
  • blood gas (venous or arterial)

Investigations to consider

  • CT/MRI, x-ray, ultrasound
  • fresh frozen section

Treatment algorithm

Contributors

Expert advisers

John Abercrombie, FRCS

General and Colorectal Surgeon

Queen’s Medical Centre

Nottingham

UK

Biography

JA is Clinical Lead for General Surgery, Getting It Right First Time.

Disclosures

JA is a council member of the Royal College of Surgeons. He also provides expert advice to Spire Healthcare on clinical management of selected cases and on improving processes for review of cases resulting in mortality.

Melvyn Jenkins-Welch, BSc(Hons), MBBS, MSc, FRCA, FFICM

Consultant Critical Care Medicine

Cardiff and Vale ULHB

Cardiff

UK

Disclosures

MJW declares that he has no competing interests.

Brian Angus, BSc, MBChB, MD, FRCP

Professor

Oxford University

Infectious Diseases Consultant

John Radcliffe Hospital

Oxford

UK

Disclosures

BA declares that he has no competing interests.

Acknowledgements

BMJ Best Practice would like to gratefully acknowledge the previous expert contributors, whose work has been retained in parts of the content:

Kevin L. Steiner, MD, PhD, DTM&H

Fellow

Division of Infectious Diseases and International Health

University of Virginia

Charlottesville

VA

William A. Petri Jr, MD, PhD, FACP

Wade Hampton Frost Professor of Epidemiology

Professor of Medicine

Microbiology and Pathology

Division of Infectious Diseases and International Health

University of Virginia

Charlottesville

VA

Disclosures: KLS and WAP declare that they have no competing interests.

Peer reviewers

Kordo Saeed, MB, ChB, MSc, FRCPath, MD

Consultant Microbiologist

University Hospital Southampton NHS Foundation Trust

Honorary Senior Lecturer

University of Southampton

Southampton

UK

Disclosures

KS declares that he has no competing interests.

Editors

Annabel Sidwell,

Section Editor and Comorbidities Editor, BMJ Best Practice

Disclosures

AS declares that she has no competing interests.

Tannaz Aliabadi-Oglesby,

Lead Section Editor, BMJ Best Practice

Disclosures

TAO declares that she has no competing interests.

Adam Mitchell,

Drug Editor, BMJ Best Practice

Disclosures

AM declares that he has no competing interests.

Use of this content is subject to our disclaimer