Anaphylaxis

Anaphylaxis presents with sudden onset of life-threatening airway and/or breathing and/or circulation problems (with or without skin changes) after exposure to a trigger (allergen).

Skin rash, wheezing and inspiratory stridor, and hypotension are the cardinal signs and symptoms.

The diagnosis is clinical. Allergy testing is helpful to prevent recurrence.

Initiating prompt treatment with intramuscular adrenaline (epinephrine) and securing the airway may save lives.

Comorbidities (e.g., coronary artery disease and COPD) may pose a treatment challenge and require expert consultation.

This topic does not cover the specialist management of anaphylaxis related to anaesthetic agents.

Anaphylaxis is a severe, generalised or systemic hypersensitivity reaction, characterised by rapidly developing life-threatening airway and/or breathing and/or circulation problems usually associated with skin and mucosal changes.[1]Johansson SG, Bieber T, Dahl R, et al. Revised nomenclature for allergy for global use: report of the Nomenclature Review Committee of the World Allergy Organization, October 2003. J Allergy Clin Immunol. 2004 May;113(5):832-6. https://www.jacionline.org/article/S0091-6749(04)00930-3/fulltext http://www.ncbi.nlm.nih.gov/pubmed/15131563?tool=bestpractice.com A systemic response is caused by the release of immune and inflammatory mediators from basophils and mast cells. Allergy to food, medication, or venoms (including bites and stings) is the most frequent cause. Non-immunological anaphylaxis, previously described as an anaphylactoid reaction, produces similar symptoms.