Last reviewed: 7 Apr 2021
Last updated: 15 May 2020



History and exam

Key diagnostic factors

  • severe diffuse or localised pain in an extremity
  • fever
  • localised swelling or erythema
  • hypotension
  • diffuse, scarlatina-like erythematous rash

Other diagnostic factors

  • acute mental status changes
  • influenza-like symptoms
  • muscular tenderness and weakness
  • abdominal pain and tenderness
  • features of myocarditis
  • endophthalmitis
  • hypothermia

Risk factors

  • diabetes mellitus
  • alcoholism
  • minor trauma and injuries with bruising, haematoma formation, or muscle strain
  • surgical procedures (e.g., vaginal delivery, breast reconstruction, caesarean section, hysterectomy, liposuction, bunionectomy)
  • single tampon used continuously for consecutive days during menses
  • using highly absorbent tampons
  • NSAID use
  • using contraceptive sponges, diaphragms, and IUDs
  • untreated strep throat

Diagnostic investigations

1st investigations to order

  • microscopy and culture (blood, wound, fluid, tissue)
  • FBC
  • prothrombin time
  • partial thromboplastin time
  • serum urea and creatinine
  • urinalysis
  • LFTs
  • creatine kinase (CK)
  • serum calcium
  • serum albumin
  • serum lactic acid

Investigations to consider

  • Staphylococcus aureus antibody testing
  • chest x-ray

Treatment algorithm


Professor of Medicine

Rosalind Franklin University of Medicine and Science

Infectious Disease Section Chief

Veteran Affairs Medical Center

North Chicago



WK declares that he has no competing interests.

Dr Khayr would like to gratefully acknowledge Dr Marie R. Baldisseri, a previous contributor to this topic. MRB declares that she has no competing interests.

Peer reviewersVIEW ALL

Associate Professor

Department of Critical Care Medicine and Department of General Surgery

Geisinger Medical Center




MJR declares that she has no competing interests.


Critical Care Division

The Methodist Hospital




JZ declares that she has no competing interests.

Professor in Medicine at University of Versailles SQY

Director of the General ICU at Raymond Poincaré Hospital (AP-HP)

Director of the Center for Clinical Research and Technology Innovation (INSERM)




DA is an author of a number of references cited in this topic.

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