Last reviewed:October 2019
Last updated:March  2019



History and exam

Key diagnostic factors

  • presence of risk factors
  • witnessed bite/sting
  • local oedema
  • local pain
  • local warmth
  • local markings
  • pruritus
  • wheal and flare
  • skin pallor
  • clamminess
  • signs of airway compromise
  • oropharyngeal oedema
  • dyspnoea
  • rales/crackles/wheeze
  • tachycardia
  • irregular pulse
  • skin flushing
  • altered alertness

Other diagnostic factors

  • pustules
  • bullseye-shaped rash
  • rash on palms and soles
  • linear raised rash
  • hypertension
  • fever
  • muscle cramp
  • diaphoresis
  • tremor
  • paraesthesia and/or fasciculations
  • generalised pain
  • nausea/vomiting
  • headache
  • abdominal pain
  • history of immunocompromised state
  • history of cardiovascular disease
  • abscess
  • necrosis
  • cough
  • hypotension
  • arthralgia
  • adenopathy

Risk factors

  • occupational or recreational exposure to insects
  • geographical exposure to insects
  • previous history of anaphylactic (or anaphylactoid) response

Diagnostic investigations

Investigations to consider

  • FBC
  • serum tryptase
  • sensitivity testing
Full details

Treatment algorithm


Tom Morrissey

Associate Professor

Department of Emergency Medicine

University of Florida




TM declares that he has no competing interests.

Tom Morrissey would like to gratefully acknowledge the assistance of Richard Vetter (MS) from the Department of Urban Entomology at the University of California.

Peer reviewersVIEW ALL

Allergist and Immunologist

Jacobs Ramirez and Freeman Allergy & Immunology

San Antonio



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

Clinical Director

Acute Medicine

Associate Medical Director

Consultant Emergency Medicine

Guy's and St Thomas' NHS Foundation Trust

Clinical Lead and Consultant

Accident Emergency Medicine

St Thomas' Hospital




AP declares that he has no competing interests.

Chairman and Professor

Department of Medicine

Professor of Pediatrics

Billy S. Guyton Distinguished Professor

University of Mississippi Medical Center




RD is an author of a reference cited in this topic.

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